Editing Infidelity (section)

==Incidence==
After the [[Kinsey Report]]s came out in the early 1950s, findings suggested that historically and cross-culturally, [[extramarital sex]] has been a matter of regulation more than sex before marriage.<ref>{{cite journal |last1=Christensen |first1=H. T. |title=A Cross-Cultural Comparison of Attitudes Toward Marital Infidelity |journal=International Journal of Comparative Sociology |date=1 March 1962 |volume=3 |issue=1 |pages=124–137 |doi=10.1177/002071526200300112 |s2cid=220874833 }}</ref>  The Kinsey Reports found that around half of men and a quarter of women studied had committed [[adultery]].<ref name=Greeley91>{{cite journal |last1=Greeley |first1=Andrew |title=Marital infidelity |journal=Society |date=May 1994 |volume=31 |issue=4 |pages=9–13 |doi=10.1007/bf02693241 |s2cid=189887196 }}</ref> The ''Janus Report on Sexual Behavior in America'' also reported that one-third of married men and a quarter of women have had an extramarital [[affair]].<ref name=Greeley91/>

According to ''[[The New York Times]]'', the most consistent data on infidelity comes from the [[University of Chicago]]'s [[General Social Survey]] (GSS). Interviews with people in [[Monogamy|monogamous]] relationships since 1972 by the GSS have shown that approximately 12% of men and 7% of women admit to having had an extramarital relationship.<ref name=":4">{{cite news |last1=Parker-Pope |first1=Tara |title=Love, sex and the changing landscape of infidelity |url=https://www.nytimes.com/2008/10/28/health/28iht-28well.17304096.html |work=The New York Times |date=28 October 2008 |access-date=23 October 2021 |archive-date=23 October 2021 |archive-url=https://web.archive.org/web/20211023161220/https://www.nytimes.com/2008/10/28/health/28iht-28well.17304096.html |url-status=live }}</ref> Results, however, vary year by year, and also by age-group surveyed. For example, one study conducted by the [[University of Washington-Seattle|University of Washington, Seattle]], found slightly, or significantly higher, rates of infidelity for populations under 35, or older than 60. In that study, which involved 19,065 people during a 15-year period, rates of infidelity among men were found to have risen from 20% to 28%, and rates for women ranged from 5% to 15%.<ref name=":4" /> In more recent nationwide surveys, several researchers found that about twice as many men as women reported having an extramarital affair.<ref name="Wiederman, M. W. 1997">{{cite journal |last1=Wiederman |first1=Michael W. |title=Extramarital sex: Prevalence and correlates in a national survey |journal=Journal of Sex Research |date=January 1997 |volume=34 |issue=2 |pages=167–174 |doi=10.1080/00224499709551881 }}</ref> A survey conducted in 1990 found that 2.2% of married participants reported having more than one partner during the past year. In general, national surveys conducted in the early 1990s reported that between 15 and 25% of married Americans reported having extramarital affairs.<ref name="Choi, K. H. 1994">{{cite journal |last1=Choi |first1=K H |last2=Catania |first2=J A |last3=Dolcini |first3=M M |title=Extramarital sex and HIV risk behavior among US adults: results from the National AIDS Behavioral Survey. |url=https://archive.org/details/sim_american-journal-of-public-health_1994-12_84_12/page/2003 |journal=American Journal of Public Health |date=December 1994 |volume=84 |issue=12 |pages=2003–2007 |doi=10.2105/ajph.84.12.2003 |pmid=7998648 |pmc=1615405 }}</ref> People who had stronger sexual interests, more permissive sexual values, lower subjective satisfaction with their partner, weaker network ties to their partner, and greater sexual opportunities were more likely to be unfaithful.<ref name="Treas, J. 2000">{{cite journal |last1=Treas |first1=Judith |last2=Giesen |first2=Deirdre |title=Sexual Infidelity Among Married and Cohabiting Americans |url=https://archive.org/details/sim_journal-of-marriage-and-family_2000-02_62_1/page/48 |journal=Journal of Marriage and Family |date=February 2000 |volume=62 |issue=1 |pages=48–60 |doi=10.1111/j.1741-3737.2000.00048.x }}</ref> Studies suggest around 30–40% of unmarried relationships and 18–20% of marriages see at least one incident of sexual infidelity.

Rates of infidelity among women are thought to increase with age. In one study, rates were higher in more recent marriages, compared with previous generations. Men were found to be only "somewhat" more likely than women to engage in infidelity, with rates for both sexes becoming increasingly similar.<ref name=BlowHartnett05/> Another study found that the likelihood of women being involved in infidelity reached a peak in the seventh year of their marriage and then declined afterward. For married men, the longer they were in relationships, the less likely they were to engage in infidelity, until the eighteenth year of marriage, at which point the chance of men engaging in infidelity began to increase.<ref>{{cite journal |last1=Liu |first1=Chien |title=A Theory of Marital Sexual Life |url=https://archive.org/details/sim_journal-of-marriage-and-family_2000-05_62_2/page/363 |journal=Journal of Marriage and Family |date=May 2000 |volume=62 |issue=2 |pages=363–374 |doi=10.1111/j.1741-3737.2000.00363.x }}</ref>

Research on pregnancy and its effects on [[Sexual desire and intimate relationships|sexual desire]] and rates of infidelity conducted in southern Spain indicated that men were more likely to engage in infidelity while their partner was pregnant. It was estimated that 1 in 10 fathers-to-be engaged in infidelity at some point during their partner's pregnancy and suggested that the likelihood of the man engaging in infidelity increases as the woman's pregnancy progresses through its [[trimesters]].<ref>{{Cite journal |last1=Fernández-Carrasco |first1=Francisco Javier |last2=Rodríguez-Díaz |first2=Luciano |last3=González-Mey |first3=Urbano |last4=Vázquez-Lara |first4=Juana María |last5=Gómez-Salgado |first5=Juan |last6=Parrón-Carreño |first6=Tesifón |date=14 February 2020 |title=Changes in Sexual Desire in Women and Their Partners during Pregnancy |journal=[[Journal of Clinical Medicine]] |language=en |volume=9 |issue=2 |pages=526 |doi=10.3390/jcm9020526 |pmid=32075159 |pmc=7074242 |issn=2077-0383|doi-access=free }}</ref>

One measure of infidelity is [[paternal discrepancy]], a situation that arises when someone who is presumed to be a child's father is in fact not the biological parent. Frequencies as high as 30% are sometimes assumed in the media, but research<ref name=2009gilding>{{cite journal |last1= Gilding |first1= Michael |year= 2005 |title= Rampant misattributed paternity: the creation of an urban myth |journal= People and Place |volume= 13 |issue= 12 |pages= 1&ndash;11 |url= http://arrow.monash.edu.au/hdl/1959.1/480786 |access-date= 2016-06-02 |archive-date= 2020-10-02 |archive-url= https://web.archive.org/web/20201002174433/https://bridges.monash.edu/articles/journal_contribution/Rampant_misattributed_paternity_the_creation_of_an_urban_myth/4975400 |url-status= live }}</ref><ref name=2009bgilding>{{cite journal |last1=Gilding |first1=Michael |title=Paternity Uncertainty and Evolutionary Psychology: How a Seemingly Capricious Occurrence Fails to Follow Laws of Greater Generality |journal=Sociology |date=February 2009 |volume=43 |issue=1 |pages=140–157 |doi=10.1177/0038038508099102 |s2cid=145367552 }}</ref> by sociologist Michael Gilding traced these overestimates back to an informal remark at a 1972 conference.<ref name=1973philipp>Philipp EE (1973) "Discussion: moral, social and ethical issues". In: Wolstenholme GEW, Fitzsimons DW, eds. ''Law and ethics of AID and embryo transfer''. Ciba Foundation symposium. Vol 17. London: Associated Scientific 63–66</ref> The detection of paternal discrepancy can occur in the context of medical [[genetic screening]],<ref name=2005bellis>{{cite journal |vauthors=Bellis MA, Hughes K, Hughes S, Ashton JR |title=Measuring paternal discrepancy and its public health consequences |journal=J Epidemiol Community Health |volume=59 |issue=9 |pages=749–54 |date=September 2005 |pmid=16100312 |pmc=1733152 |doi=10.1136/jech.2005.036517 }}</ref> in genetic family name research,<ref>{{cite journal | last1 = Sykes | first1 = B | last2 = Irven | first2 = C | year = 2000 | title = Surnames and the Y chromosome | journal = Am J Hum Genet | volume = 66 | issue = 4| pages = 1417–1419 | doi=10.1086/302850 | pmid=10739766 | pmc=1288207}}</ref><ref name=2009king>{{cite journal |last1=King |first1=T. E. |last2=Jobling |first2=M. A. |title=Founders, Drift, and Infidelity: The Relationship between Y Chromosome Diversity and Patrilineal Surnames |journal=Molecular Biology and Evolution |date=1 May 2009 |volume=26 |issue=5 |pages=1093–1102 |doi=10.1093/molbev/msp022 |pmid=19204044 |pmc=2668828 }}</ref> and in immigration testing.<ref name="ForsterEtAl">{{cite journal | last1 = Forster | first1 = P | last2 = Hohoff | first2 = C | last3 = Dunkelmann | first3 = B | last4 = Schürenkamp | first4 = M | last5 = Pfeiffer | first5 = H | last6 = Neuhuber | first6 = F | last7 = Brinkmann | first7 = B | year = 2015 | title = Elevated germline mutation rate in teenage fathers | journal = Proc Biol Sci | volume = 282 | issue = 1803| page = 20142898 | doi=10.1098/rspb.2014.2898 | pmid=25694621 | pmc=4345458}}</ref> Such studies show that paternal discrepancy is, in fact, less than 10% among the sampled [[African people|African]] populations, less than 5% among the sampled [[Native Americans in the United States|Native American]] and [[Polynesians|Polynesian]] populations, less than 2% of the sampled [[Middle Eastern peoples|Middle Eastern]] population, and generally 1–2% among [[Europeans|European]] samples.<ref name="2005bellis"/>

===Gender===
Differences in sexual infidelity as a function of gender have been commonly reported. The National Health and Social Life Survey found that 4% of married men, 16% of cohabiting men, and 37% of dating men engaged in acts of sexual infidelity in the previous year compared to 1% of married women, 8% of cohabiting women, and 17% of women in dating relationships.<ref name=Lalasz11>{{cite journal | last1 = Lalasz | first1 = C. B. | last2 = Weigel | first2 = D. J. | year = 2011 | title = Understanding the relationship between gender and extradyadic relations: The mediating role of sensation seeking on intentions to engage in sexual infidelity | url = https://archive.org/details/sim_personality-and-individual-differences_2011-05_50_7/page/1079 | journal = Personality and Individual Differences | volume = 50 | issue = 7| pages = 1079–1083 | doi=10.1016/j.paid.2011.01.029}}</ref> These differences have been generally thought due to evolutionary pressures that motivate men towards sexual opportunity and women towards commitment to one partner (for reasons such as reproductive success, stability, and social expectations). In addition, recent research finds that differences in gender may possibly be explained by other mechanisms including power and sensations seeking. For example, one study found that some women in more financially independent and higher positions of power, were also more likely to be more unfaithful to their partners.<ref>{{cite journal | last1 = Lammers | first1 = J. | last2 = Stoker | first2 = J. I. | last3 = Jordan | first3 = J. | last4 = Pollmann | first4 = M. | last5 = Stapel | first5 = D. A. | year = 2011 | title = Power increases infidelity among men and women | url = https://archive.org/details/sim_psychological-science_2011-09_22_9/page/1191 | journal = Psychological Science | volume = 22 | issue = 9| pages = 1191–1197 | doi=10.1177/0956797611416252 | pmid=21771963| s2cid = 11385458 }}</ref> In another study, when the tendency to sensation seek (i.e., engage in risky behaviours) was controlled for, there were no gender differences in the likelihood to being unfaithful.<ref name=Lalasz11/> These findings suggest there may be various factors that might influence the likelihood of some individuals to engage in extradyadic relationships, and that such factors may account for observed gender differences beyond actual gender and evolutionary pressures associated with each.

====Gender differences====
There is currently debate in the field of [[evolutionary psychology]] whether an innate, evolved sex difference exists between men and women in response to an act of infidelity; this is often called a "sex difference". A study published in 2002 suggested there may be sex differences in jealousy.<ref name="DeSteno, D. 2002">{{cite journal | last1 = DeSteno | first1 = D. | last2 = Bartlett | first2 = M. Y. | last3 = Braverman | first3 = J. | last4 = Salovey | first4 = P. | year = 2002 | title = Sex differences in jealousy: Evolutionary mechanism or artifact of measurement? | url = https://pdfs.semanticscholar.org/c91b/c25e64fa17bede652c8ec43eba6a52bc853f.pdf | archive-url = https://web.archive.org/web/20180730080729/https://pdfs.semanticscholar.org/c91b/c25e64fa17bede652c8ec43eba6a52bc853f.pdf | url-status = dead | archive-date = 2018-07-30 | journal = [[Journal of Personality and Social Psychology]] | volume = 83 | issue = 5| pages = 1103–1116 | doi =  10.1037/0022-3514.83.5.1103 | pmid = 12416915 | citeseerx = 10.1.1.616.5778 | s2cid = 10537789 }}</ref> Those that posit a sex difference exists state that men are 60% more likely to be disturbed by an act of sexual infidelity (having one's partner engage in sexual relations with another), whereas women are 83% more likely to be disturbed by an act of emotional infidelity (having one's partner fall in love with another).<ref name="Buss92" /> Those against this model argue that there is no difference between men and women in their response to an act of infidelity.<ref name="Buss92">{{cite journal|last=Buss, D. M.|author2=Larsen, R. J.|author3=Westen, D.|author4=Semmelroth, J.|year=1992|title=Sex Differences in Jealousy—Evolution, Physiology, and Psychology|url=https://archive.org/details/sim_psychological-science_1992-07_3_4/page/251|journal=Psychological Science|volume=3|issue=4|pages=251–255|doi=10.1111/j.1467-9280.1992.tb00038.x|s2cid=27388562}}<!--|access-date=2013-12-12 --></ref><ref name="Miller, S. L. 2009">{{cite journal | last1 = Miller | first1 = S. L. | last2 = Maner | first2 = J. K. | year = 2009 | title = Sex differences in response to sexual versus emotional infidelity: The moderating role of individual differences | url = https://archive.org/details/sim_personality-and-individual-differences_2009-02_46_3/page/287 | journal = Personality and Individual Differences | volume = 46 | issue = 3| pages = 287–291 | doi = 10.1016/j.paid.2008.10.013 }}</ref> From an evolutionary perspective, men are theorized to maximize their [[Fitness (biology)|fitness]] by investing as little as possible in their offspring and producing as many offspring as possible, due to the risk of males investing in children that are not theirs. Women, who do not face the risk of cuckoldry, are theorized to maximize their fitness by investing as much as possible in their offspring because they invest at least nine months of resources towards their offspring in pregnancy.<ref name="Miller, S. L. 2009" /> Maximizing female fitness is theorized to require males in the relationship to invest all their resources in the offspring. These conflicting strategies are theorized to have resulted in selection of different jealousy mechanisms that are designed to enhance the fitness of the respective gender.<ref name="Murphy, S. M. 2006">{{cite journal | last1 = Murphy | first1 = S. M. | last2 = Vallacher | first2 = R. R. | last3 = Shackelford | first3 = T. K. | last4 = Bjorklund | first4 = D. F. | last5 = Yunger | first5 = J. L. | year = 2006 | title = Relationship experience as a predictor of romantic jealousy | url = https://archive.org/details/sim_personality-and-individual-differences_2006-03_40_4/page/761 | journal = Personality and Individual Differences | volume = 40 | issue = 4| pages = 761–769 | doi = 10.1016/j.paid.2005.09.004 }}</ref>

A common way to test whether an innate jealousy response exists between sexes is to use a forced-choice questionnaire. This style of questionnaire asks participants "yes or no" and "response A or response B" style questions about certain scenarios. For example, a question might ask, "If you found your partner cheating on you would you be more upset by (A) the sexual involvement or (B) the emotional involvement". Many studies using forced choice questionnaires have found statistically significant results supporting an innate sex difference between men and women.<ref name="Murphy, S. M. 2006" />  Furthermore, studies have shown that this observation holds across many cultures, although the magnitudes of the sex difference vary within sexes across cultures.<ref>{{cite journal | last1 = Buunk | first1 = B. P. | last2 = Angleitner | first2 = A. | last3 = Oubaid | first3 = V. | last4 = Buss | first4 = D. M. | year = 1996 | title = Sex differences in jealousy in evolutionary and cultural perspective: Tests from the Netherlands, Germany, and the United States | url = https://archive.org/details/sim_psychological-science_1996-11_7_6/page/359 | journal = Psychological Science | volume = 7 | issue = 6| pages = 359–363 | doi = 10.1111/j.1467-9280.1996.tb00389.x | s2cid = 27485391 }}</ref>

Although forced-choice questionnaires show a statistically significant sex-difference, critics of the theory of evolved sex differences in jealousy question these findings. In consideration of the entire body of work on sex differences, C. F. Harris asserted that when methods other than forced-choice questionnaires are used to identify an innate sex difference, inconsistencies between studies begin to arise.<ref name="Harris, C. R. 2003">{{cite journal | last1 = Harris | first1 = C. R. | year = 2003 | title = A review of sex differences in sexual jealousy, including self-report data, psychophysiological responses, interpersonal violence, and morbid jealousy | journal = Personality and Social Psychology Review | volume = 7 | issue = 2| pages = 102–128 | doi = 10.1207/S15327957PSPR0702_102-128 | pmid=12676643| s2cid = 7357390 }}</ref> For example, researchers found that women sometimes report feeling more intense jealousy in response to both sexual and emotional infidelity. The results of these studies also depended on the context in which the participants were made to describe what type of jealousy they felt, as well as the intensity of their jealousy.<ref name="Sagarin, B. J. 2005">{{cite journal | last1 = Sagarin | first1 = B. J. | year = 2005 | title = Reconsidering evolved sex differences in jealousy: Comment on Harris (2003) | journal = Personality and Social Psychology Review | volume = 9 | issue = 1| pages = 62–75 | doi = 10.1207/s15327957pspr0901_5 | pmid = 15745865 | s2cid = 10951706 }}</ref>

In her meta-analysis, Harris raises the question of whether forced choice questionnaires actually measure what they purport: jealousy itself and evidence that differences in jealousy arise from innate mechanisms.<ref name="Harris, C. R. 2003" /> Her [[meta-analysis]] reveals that sex-differences are almost exclusively found in forced-choice studies. According to Harris, a meta-analysis of multiple types of studies should indicate a convergence of evidence and multiple operationalizations. This is not the case, which raises the question as to the validity of forced-choice studies. DeSteno and Bartlett (2002) further support this argument by providing evidence which indicates that significant results of forced-choice studies may actually be an artifact of measurement; this finding would invalidate many of the claims made by those "in favor" of an "innate" sex difference.<ref name="DeSteno, D. 2002" /> Even those "in favor" of sex-differences admit that certain lines of research, such as homicide studies, suggest against the possibility of sex-differences.<ref name="Sagarin, B. J. 2005" />

These inconsistent results have led researchers to propose novel theories that attempt to explain the sex differences observed in certain studies. One theory that has been hypothesized to explain why men and women both report more distress to emotional infidelity than sexual infidelity is borrowed from childhood [[Attachment theory|attachment theories]].  Studies have found that [[attachment styles]] of adults are consistent with their self-reported relationship histories.<ref>{{cite journal | last1 = Levy | first1 = K. N. | last2 = Blatt | first2 = S. J. | last3 = Shaver | first3 = P. R. | year = 1998 | title = Attachment styles and parental representations | url = https://archive.org/details/sim_journal-of-personality-and-social-psychology_1998-02_74_2/page/407 | journal = Journal of Personality and Social Psychology | volume = 74 | issue = 2| pages = 407–419 | doi=10.1037/0022-3514.74.2.407}}</ref> For example, more men are reported to have an insecure, dismissing avoidant attachment style; where these "individuals often attempt to minimize or constrict emotional experience, deny needs for intimacy, are highly invested in autonomy, and are more sexually promiscuous than individuals who have other attachment styles".<ref name="Levy, K. N. 2010">{{cite journal | last1 = Levy | first1 = K. N. | last2 = Kelly | first2 = K. M. | year = 2010 | title = Sex differences in jealousy A contribution from attachment theory | url = https://archive.org/details/sim_psychological-science_2010-02_21_2/page/168 | journal = Psychological Science | volume = 21 | issue = 2| pages = 168–173 | doi=10.1177/0956797609357708 | pmid=20424039| s2cid = 206584973 }}</ref>  Levy and Kelly (2010) tested this theory and found that adult attachment styles strongly correlate to which type of infidelity elicited more jealousy.<ref name="Levy, K. N. 2010" /> Individuals who have secure attachment styles often report that emotional infidelity is more upsetting whereas dismissing attachment styles were more likely to find sexual infidelity more upsetting.<ref name="Levy, K. N. 2010" /> Their study did report that men in general were more likely than women to report sexual infidelity as more distressing, however this could be related to more men having a dismissing attachment style. The authors propose that a social mechanism may be responsible for the observed results. In other words, replicable sex differences in emotion and sexual jealousy could be a function of a social function. Similar studies focusing on the masculinization and feminization by society also argue for a social explanation, while discounting an evolutionary explanation.<ref>{{cite journal | last1 = Ward | first1 = J. | last2 = Voracek | first2 = M. | year = 2004 | title = Evolutionary and social cognitive explanations of sex differences in romantic jealousy | journal = Australian Journal of Psychology | volume = 56 | issue = 3| pages = 165–171 | doi = 10.1080/00049530412331283381 | doi-access = free }}</ref>

A 2015 study found a correlation between [[Vasopressin receptor 1A|AVPR1A]] expression and predisposition to [[extramarital sex|extrapair mating]] in women but not in men.<ref>{{cite journal | title=Genetic analysis of human extrapair mating: heritability, between-sex correlation, and receptor genes for vasopressin and oxytocin |author1=Zietsch, Brendan P. |author2=Westberg, Lars |author3=Santtila, Pekka |author4=Jern, Patrick | journal=Evolution & Human Behavior | year=2015 | volume=36 | issue=2 | pages=130–136 |quote=We find strong genetic effects on extrapair mating in women and, for the first time, in men. |doi=10.1016/j.evolhumbehav.2014.10.001|bibcode=2015EHumB..36..130Z |url = http://espace.library.uq.edu.au/view/UQ:352859/UQ352859_OA.pdf}}</ref>

===Sexual orientation===
Evolutionary researchers have suggested that humans have innate mechanisms{{define|date=December 2018}} that contribute to why they become sexually jealous, this is especially true for certain types of infidelity.<ref>{{cite journal |last1=Harris |first1=Christine R. |title=The Evolution of Jealousy: Did men and women, facing different selective pressures, evolve different "brands" of jealousy? Recent evidence suggests not |journal=American Scientist |date=2004 |volume=92 |issue=1 |pages=62–71 |doi=10.1511/2004.1.62 |jstor=27858334 }}</ref> It has been hypothesized that heterosexual men have developed an innate psychological mechanism that responds to the threat of sexual infidelity more than emotional infidelity, and vice versa for heterosexual women<ref name="Schmitt, D. P. 2005"/> because potential [[cuckoldry]] is more detrimental to the male, who could potentially invest in offspring of another male, while for females emotional infidelity is more worrisome because they could lose the parental investment to another woman's offspring, therefore affecting their chances of survival.<ref name="Schmitt, D. P. 2005"/> However, more recent studies suggest that increasingly both men and women would find emotional infidelity psychologically worse.<ref name="Harris, C. R. 2002">{{cite journal | last1 = Harris | first1 = C. R. | year = 2002 | title = Sexual and romantic jealousy in heterosexual and homosexual adults | journal = Psychological Science | volume = 13 | issue = 1| pages = 7–12 | doi=10.1111/1467-9280.00402 | pmid=11892782| s2cid = 18815461 }}</ref>

Symons (1979) determined that sexual jealousy is the major reason that many homosexual men are unsuccessful in maintaining monogamous relationships<ref name="Harris, C. R. 2002"/> and suggests that all men are innately disposed to want sexual variation, with the difference between heterosexual and homosexual men being that homosexual men can find willing partners more often for casual sex, and thus satisfy this innate desire for sexual variety.<ref name="Harris, C. R. 2002"/> However, according to this view, all men can be "hard wired" to be sexually jealous, and therefore [[gay men]] could be more upset by sexual infidelity than by emotional infidelity, and that lesbians could be more upset by emotional infidelity than sexual.<ref name="Harris, C. R. 2002"/> Recent studies suggest that it may not be an innate mechanism, rather depends on the importance placed on sexual exclusivity. Peplau and Cochran (1983) found that sexual exclusivity was much more important to heterosexual men and women compared to homosexual men and women. This theory suggests that it is not sexuality that may lead to differences but that people are prone to jealousy in domains that are especially important to them.<ref>{{cite book |last1=Salovey |first1=Peter |title=The Psychology of Jealousy and Envy |date=1991 |publisher=Guilford Press |isbn=978-0-89862-555-4 |pages=271–286 }}</ref> Barah and Lipton argue that heterosexual couples may cheat just as much as homosexual relationships.<ref>{{Cite book|title=The Myth of Monogamy: Fidelity and Infidelity in Animals and People |last=Barash & Lipton|first=D.P. & J.E.|publisher=Henry Holt|year=2001|location=New York}}{{page needed|date=October 2021}}</ref>

Harris (2002) tested these hypotheses among 210 individuals: 48 homosexual women, 50 homosexual men, 40 heterosexual women, and 49 heterosexual men.<ref name="Harris, C. R. 2002"/> Results found that more heterosexual than homosexual individuals picked sexual infidelity as worse than emotional infidelity, with heterosexual men being the highest, and that when forced to choose, gay men overwhelmingly predicted emotional infidelity would be more troubling than sexual infidelity.<ref name="Harris, C. R. 2002"/> These findings contradict Symons (1979) suggestion that there would be no gender difference in predicted responses to infidelity by sexual orientation.<ref name="Harris, C. R. 2002"/> Blow and Bartlett (2005) suggest that even though sex outside of a homosexual relationship might be seen as more acceptable in some relationships, the consequences of infidelity do not occur without pain or jealousy.<ref name=BlowHartnett05/>

Heterosexuals rated emotional and sexual infidelity as more emotionally distressing than did lesbian and gay individuals. Sex and sexual orientation differences emerged regarding the degree to which specific emotions were reported in response to sexual and emotional infidelity.  Few researchers have explored the influence of sexual orientation on which type of infidelity is viewed as more distressing.<ref name="Leeker12">{{cite journal|year=2012|title=Effects of sex, sexual orientation, infidelity expectations, and love on distress related to emotional and sexual infidelity|journal=Journal of Marital and Family Therapy|volume=40|issue=1|pages=68–91|doi=10.1111/j.1752-0606.2012.00331.x|pmid=25059413|hdl-access=free|author1-last=Leeker|author1-first=O.|author2-last=Carlozzi|author2-first=A.|hdl=11244/7190}}</ref>

Summarizing the findings from these studies, heterosexual men seem to be more distressed by sexual infidelity than heterosexual women, lesbian women, and gay men.<ref name="Leeker12" /> These latter three groups seem more responsible for this difference by reporting similarly higher levels of distress toward emotional infidelity than heterosexual men.<ref name="Leeker12" /> However, within-sex analyses reveal that heterosexual men tend to rate emotional infidelity as more distressing than sexual infidelity.<ref>{{Cite web|url=https://www.psychologytoday.com/blog/media-spotlight/201404/after-infidelity|title=After Infidelity|website=Psychology Today|access-date=2017-11-09}}</ref>