According to recent research (Finchan & May, 2017), 2 to 4 percent of spouses report having had extramarital sex within the preceding 12 months. Lifetime rates of infidelity are higher, of course. In contrast to past surveys, men and women report having about the same rate of infidelity. Infidelity is the most common reported cause of divorce. They note a large number of factors contribute to infidelity:
What prevents couples from cheating?
The Journal of Sex Research (Ziv, Lubin & Asher, 2017) set out to study married couples to see what their attitudes toward infidelity were in terms of what they thought would prevent them from going outside their marriage. Researchers noted that there are several theories related to infidelity to take into consideration. Economic theories such as the "interdependence" model and the "social investment" model suggest that the balance between costs and benefits of infidelity may determine whether people cheat. If a couple has invested more in one another, their motivation to maintain the relationship will be stronger. Therefore, to decide to switch mates, the prospective new mate has to be significantly better than the existing mate.
They discuss the role of social mores in preventing infidelity. Within a large number of cultures, marital infidelity is considered wrong, and infidelity is typically kept secret and/or condemned. They note, for instance, that according to a 1994 survey, prior researchers found that 77 percent of Americans judged extramarital sex to be "always wrong." Therefore, they predict that moral beliefs will play a strong role in preventing affairs.
From an evolutionary psychology point of view, they discuss differences in how theorists conceptualize infidelity for men versus women, although arguably these attitudes are shifting as our conceptions of gender change. Nevertheless, the standard model says that monogamy may block males from an inherent tendency to mate as frequently as possible, while preventing women from choosing more genetically desirable mates by narrowing down their choices once married. Therefore, they predict that men are more likely to be open to infidelity, though statistics on actual gender differences in infidelity do not definitively support the finding that men cheat more than women (as reflected in the recent data cited above).
Men and women, in prior work, have been seen as having markedly different attitudes about infidelity. Men are characteristically viewed as being more concerned about their partner's physical transgressions, and women about their partner's emotional faithfulness. According to evolutionary models, this is because men are wired to be more concerned with ensuring paternity, whereas women are more focused on long-term commitment, though these theories remain unproven. In terms of social norms, men are generally seen as engaging in sexual activity more to fulfill basic physical needs with less concern for emotional connection, and women are more focused on establishing a love relationship. Therefore, from a societal point of view, there may be a greater willingness to forgive men when they are unfaithful.
In seeking to understand what stops people from being unfaithful, given the various permissive and preventive factors, Ziv and colleagues designed two studies to explore what people report would hold them back when faced with temptation.
In the first study, they administered a 34-item questionnaire to 110 people, 36 men and 74 women, ranging in age from 24 to 60. All were married at least two years, had at least one child, and were living together at the time of the study. The questions looked at various factors which would go against infidelity: for example, "I might have to leave home," "I might end up alone," "It is not moral," "I will cause mental harm to my children," and "I love my spouse." They analyzed the responses to determine which major factors emerged, and found four main factors covered all the responses:
1. Moral Standards
2. Effects on the Children
3. Fear of Remaining Alone
4. Effects on Other People (Especially the Extramarital Sex Partner)
They found that women consider themselves less prone to extramarital affairs compared to men, who consider themselves more likely to be unfaithful. Further, they found that women had stronger moral objections, which accounted for their self-rating, and that concern for effect on children was a bigger contributor to the moral factor for women than men. The other factors were also significant, and did not vary overall between women and men, though the moral factor remained of greatest significance overall:
In the second study, the researchers repeated the survey with a larger sample of 348 people, 163 of them men, married at least one year with at least one child, and between 20 and 45 years of age. In addition to seeking to further validate the four-factor model, they included additional questions about duration of marriage and level of religious belief, in order to see how these factors might affect reluctance to engage in extramarital sex. Further, they rated what respondents considered infidelity to be, ranging from use of internet pornography, to a single sexual chat, to multiple sexual chats, to one instance of physical contact, and finally to multiple instances of intimate physical contact with the same partner.
Overall, they found that the greater the degree of contact outside the marriage, the more likely respondents were to consider it infidelity. They found that for any given behavior, however, men were less likely to consider it to be infidelity. In addition, the less religious respondents were, the less likely they were to consider any given behavior to be infidelity. Interestingly, how long people had been married did not influence what they considered to be infidelity.
Again, women rated themselves as more likely to be able to resist infidelity than men. This was consistent for longer marriages as well — men, but not women, reported that they were more likely to engage in extramarital sex the longer they had been married.
While the overall four factors were significant, with moral standards being the largest source of resistance to infidelity, in the second study there was no significant difference to the degree of moral reluctance between men and women. However, moral standards were a greater factor for more religious respondents, while fear of being alone was greater for more secular respondents.
In addition to the survey, participants filled in open comments about their motivations. Respondents who were willing to engage in extramarital contact reported the following reasons why they would: being tempted, acting on impulse, feeling passion, and having difficulty in their marriage. Those who were disinclined to go outside their marriages reported the following factors: monogamy being moral, loyalty, love, fear of hurting children and spouse, and religious proscription.
They offer a detailed discussion of their findings, noting some support for evolutionary views arguing for differences between men and women's views on infidelity, as well as discussing the role of social factors, including moral and religious views on marriage. Noting that future research examining attitudes about actual situations in which couples are faced with the real possibility of infidelity is necessary to develop a deeper understanding of how people decide to engage in extramarital relationships, they conclude:
"According to the current results, spouses of both genders are less likely to be involved in extramarital sex when they are young, their marriage is still in its early stages, and any children are relatively young and vulnerable. During this phase of child rearing, investment in the relationship, family, and children serves as a strong barrier.
"However, at a certain point, our evolutionary heritage outweighs investment-related factors as the driving force behind sexual behavior. Our results support suggestions by others that women’s rates of infidelity peak around age 40 to 45, shortly before menopause. It may be that, for women, the approach of menopause upsets the equilibrium between competing impulses achieved when the children are relatively young — that is, between the evolutionary drive to produce more children while one is still fertile, and the desire to invest in those already existing."
Because breach of trust is one of the major factors people consider when contemplating breaking up, it's important to understand what keeps people from cheating.
To learn more about repeating patterns of infidelity, this follow-up piece addresses recent research on that subject.
Fincham, F. D. & May, R. W. (2017). Infidelity in romantic relationships. Current Opinion in Psychology, 13:70-74. DOI: 10.1016/j.copsyc.2016.03.008
Ziv, I., Lubin, O. B., & Asher, S. (2017). “I Swear I Will Never Betray You”: Factors Reported by Spouses as Helping Them Resist Extramarital Sex in Relation to Gender, Marriage Length, and Religiosity, The Journal of Sex Research. DOI: 10.1080/00224499.2017.1347602