- Infidelity is strongly predicted by gradual deterioration in relationship quality.
- Infidelity affects levels of wellbeing more negatively for perpetrators than for victims.
- Women are more likely than men to benefit from initiating affairs.
Infidelity is condemned almost universally, and seen as the most egregious transgression in a relationship. Couples often cite infidelity as the reason for separation, and it is the most common reason given for divorce. Yet infidelity is also common, with one in five men and one in eight women admitting to it.
Who Is Most Likely to Cheat?
Research has found several predictors of infidelity. For example, we know that men are more likely to cheat, and that the gender gap widens with age. A 2018 study by James McNulty and colleagues at Florida State University also found that infidelity was more common among those less satisfied with their current relationships.
Physical attractiveness also plays a role. Attractive women are less likely to have an affair; not so for men. Partner attractiveness matters, too. Men (but not women) are “more likely to be unfaithful when their partners were less attractive.”
Personal background, habits, and attitudes matter, too. Those who grew up in intact families are less likely to cheat, as are those who attend religious services regularly, and those who identify as Republicans.
Childhood attachment may also play a role. Michelle Russell and colleagues (2013) at Florida State found that “spouses were more likely to perpetrate infidelity when either they or their partner was high (vs. low) in attachment anxiety.” Moreover, “partner attachment avoidance was negatively associated with infidelity, indicating that spouses were less likely to perpetrate infidelity when their partner was high (vs. low) in attachment avoidance.”
Social power is also a player in the infidelity equation. Dutch psychologist Joris Lammers and colleagues found that “elevated power is positively associated with infidelity because power increases confidence in the ability to attract partners.”
The Link Between Infidelity and Relationship Problems
Research has documented a strong correlation between infidelity and a range of relationship problems. Yet correlation does not imply causation. A central question for infidelity researchers has to do with the "causal arrow problem": Infidelity and marital strife tend to correlate. Which is the cause and which is the effect?
A recent (2022) study from Germany sought to provide answers. The researchers used a nationally representative sample of over 12,000 German adults, followed for up to 12 years (between 2008 and 2020) to examine the relationship dynamics around infidelity. The researchers documented over 1,000 infidelity events in their sample.
They looked at whether decreases in well-being in both partners either preceded or followed infidelity, and compared these data with a matched control group of couples who did not experience infidelity. The researchers collected data on both relationship satisfaction and personal well-being, to explore the potential impact of infidelity on the individual participants.
Several results stood out.
First, as one would expect, infidelity is more likely to happen in relationships of poor quality. “Both members of the couples who experienced infidelity during the study period were more likely to report lower levels of personal and relationship well-being and higher levels of relationship conflict, on average across the years," according to the researchers. "Individuals who committed infidelity and their partners scored lower on life satisfaction, reported lower relationship satisfaction, and reported higher relationship conflict, on average across the years, compared with individuals in the control sample.” These findings align with common sense, as well as similar results in the recent literature.
Second, infidelity is preceded by a gradual decline in relationship quality. “For both perpetrators and victims of infidelity, we observed a gradual deterioration in most indicators of relationship well-being that started before the event… Both perpetrators and victims of infidelity experienced a decrease in relationship satisfaction and admiration and an increase in relationship conflict prior to infidelity events.” In other words, infidelity is more likely to happen when low-quality relationships deteriorate further.
Third (and surprisingly, perhaps), the study found that the well-being of initiators of infidelity decreased more than that of their betrayed partners. “Perpetrators of infidelity experienced a baseline shift in well-being: During the time after (relative to before) the event, perpetrators reported lower self-esteem, lower relationship satisfaction and intimacy, and more relationship conflicts. In contrast, the evidence for a baseline shift in well-being was less conclusive for victims of infidelity: They reported less self-esteem and more relationship conflict after (vs. before) they were cheated on but experienced no change in other indicators of well-being.“
Fourth, with few exceptions, relationship recovery post-infidelity is difficult. “Neither victims nor perpetrators seemed to bounce back to their initial levels of relationship well-being. However, a more consistent socialization pattern emerged with respect to personal well-being: Both victims and perpetrators experienced a gradual increase in life satisfaction and self-esteem in the years following the event.”
In other words, individuals may recover more easily from infidelity than do relationships. Sometimes, the real victim of infidelity is not any of the individuals involved, but the union between them.
Fifth, the authors used their data to test competing theories of post-infidelity behavior. On one hand, the "investment model" predicts that high-commitment partners will be more likely to forgive their partners, as they are more willing to invest in relationship maintenance. On the other, expectancy violation theory argues that highly committed individuals will be less likely to forget and forgive, because their disappointment at their partner’s violation would be stronger than that of less committed individuals.
The authors' data provide support for the latter. They note: “Consistent with the expectancy violation theory, higher (vs. lower) levels of commitment were associated with worse adjustment (for both partners)… following infidelity.”
Finally, the data suggest that gender plays a role in the dynamics of infidelity. Given the popular belief that men are more inclined toward infidelity, one may assume that they stand to benefit more from it. Surprisingly, however, male initiators of infidelity “were more negatively affected by the event” than female initiators. Women who initiated infidelity “tended to experience a gradual increase (often in the shape of a rebound following pre-event declines) in personal well-being after the event.”
In fact, the results suggest that two groups tend to benefit from infidelity: people with low relationship commitment, and women. Infidelity within the former group is beneficial perhaps because lower levels of commitment beget lower levels of hurt and disappointment, insufficient to overwhelm the upside of infidelity (excitement, novelty, intimacy, pleasure, etc.). Also, infidelity in those relationships may provide a path toward finding high-commitment relationships.
Regarding the positive effects on women, the authors speculate that women’s infidelity is more often motivated by relationship dissatisfaction than men’s and cite prior research suggesting that infidelity committed for that reason is more likely to lead to positive outcomes. They also propose that women’s infidelity “may be a wake-up call for their partners, leading to positive behavioral change.”
It is also possible that contemporary women are strongly motivated—and increasingly free and able—to satisfy their psychological and relationship needs, and feel less restricted in this pursuit by fear (for their economic and physical well-being) and oppressive social mores.
A friend of mine likes to say that "nobody finds God because they're happy." Likewise with infidelity—it is usually initiated by people who are unhappy in their relationships. Alas, infidelity is more likely to exacerbate rather than alleviate that unhappiness.
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