The following is from an article in Psychology Today featuring the research of Dr. Frank Fincham and Dr. Ross May. You can read the entire article here.
Research on the predictors of infidelity has linked the behavior to an array of personality, situational, and demographic variables. While some of those, such as low religiosity or marital dissatisfaction, are intuitive, others are not. For example, one study has identified the wife’s pregnancy as a risk factor for the husband’s infidelity.
Recently, Frank Fincham and Ross May of Florida State University published a summary of “the current state of research on the prediction of infidelity” in which they highlighted several interesting findings.
For example, the authors estimate that 20-25 percent of marriages experience infidelity at some point. Infidelity tends to increase in the summer, likely due to increased travel during that season, which provides easier opportunities for covert activity. Moreover, infidelity rates increased markedly between the early 1990s and the mid-2000s, particularly in older individuals, likely due in part to the introduction of erection drugs such as Viagra. Cohabitation before marriage is associated with increased likelihood of cheating (perhaps through its association with more permissive attitudes about sex).
Like most complex human social behaviors, infidelity is multiply determined, which means that it has many causes that may interact in complex ways. One example: Relationship dissatisfaction strongly predicts infidelity, but only in people who are not very religious. Acknowledging this complexity, Fincham and May nevertheless identify four main classes of infidelity determinants:
Demographic variables: Men are more likely to have affairs than women—the disparity is due in part to the fact that more men than women visit prostitutes—although the gap appears to be closing, particularly among young people (in part due to women’s increased financial independence and social mobility).
Individual characteristics: People high in narcissism and neuroticism are more prone to infidelity. As mentioned earlier, insecure attachment style is also a predictor, as are a history of promiscuity and more permissive attitudes toward sex. A history of parental infidelity also predicts infidelity. Unfaithful parents beget unfaithful children, although of course many exceptions exist.
Relationship variables: The best proximal predictor of infidelity appears to be relationship satisfaction. Not surprisingly, relationship commitment is also strongly predictive. Research has suggested that satisfaction and infidelity have a reciprocal relationship, influencing each other. Finally, partners who are more alike (in religion, values, education etc.) are less likely to stray (perhaps in part because similarity begets more satisfying relationship).
Context: Work environment is related to the likelihood of infidelity, according to research. Specifically, work that requires much travel, and/or involves personal contact with potential mates and a large proportion of opposite-sex coworkers predicts higher odds of infidelity. Family constellations with one working and one stay-at-home spouse are also at higher risk for infidelity.
Religiosity is another factor. Specifically, attendance of religious services is reliably predictive of lower rate of affairs. Additionally, those who take the bible as the literal word of God are also less likely to stray.
Finally, as with all things sexual, the Internet provides a new context within which infidelity occurs. In general, people who seek sex on the Internet are more likely to have affairs, and a majority of those who look for sex online end up having real-world sex with the partner they met online, often in secret. Moreover ‘Internet infidelity,’ although difficult to define and research, is increasingly becoming a source of relationship stress and strife deserving of further study—as well as its own future column.