When doubt creeps in: Study sheds light on the toll of suspected infidelity

Trust is the cornerstone of any strong marriage, but what happens when that trust is broken — or even just doubted? A new study in Family Process highlights that merely suspecting a partner of infidelity is strongly linked to lower levels of happiness in marriage.

While infidelity is a well-known cause of relationship breakdowns, little research had been conducted on how a partner’s belief or suspicion of infidelity might influence the dynamics of a marriage. The researchers aimed to fill this gap by examining not only the prevalence of different types of infidelity but also how these variations impact the happiness and satisfaction of both partners in a relationship.

The study reanalyzed data from the National Couples Survey, which was originally designed to explore contraceptive decision-making among couples. This survey, conducted between 2005 and 2006, involved 236 married couples from four U.S. cities: Seattle, Durham, St. Louis, and Baltimore. On average, the couples had been married for about five years, and the study included only those who were not pregnant, postpartum, or seeking to become pregnant.

Participants were asked two key questions: whether they had engaged in extramarital sex since getting married and whether they believed their spouse had done so. Relationship satisfaction was measured using a straightforward scale where participants rated their overall happiness in the marriage.

About 12% of men and 9% of women reported having engaged in extramarital sex at some point during their marriage. These figures are somewhat lower than previous estimates, likely because the sample consisted only of currently married couples. Among husbands who admitted to extramarital sex, 62.1% of their wives were aware of the infidelity, while 57.1% of husbands knew when their wives had been unfaithful. Conversely, 9.1% of wives and 7.4% of husbands suspected their spouses of infidelity despite their partners denying it.

The study categorized couples into four distinct groups based on their responses: (1) couples where neither partner reported or suspected infidelity, (2) couples where one partner suspected infidelity but the other partner reported no infidelity, (3) couples where one partner had engaged in extramarital sex but kept it a secret, and (4) couples where the infidelity was known to both partners. Most participants fell into the first category, with 80% of men and 84% of women reporting neither engaging in nor suspecting infidelity.

When the researchers examined relationship satisfaction across these groups, they found significant differences. Both men and women in the groups where infidelity was suspected, secret, or known reported lower levels of marital satisfaction compared to those in the no-infidelity group. Notably, the lowest levels of satisfaction were reported by those whose infidelity was known to their partner. This suggests that the awareness of infidelity might be particularly damaging to relationship happiness, possibly due to the breach of trust and the emotional turmoil that follows such revelations.

The study also revealed that it was not just the act of infidelity itself that mattered but also the suspicion of it. Both men and women who suspected their partner of cheating, even if those suspicions were unfounded, experienced lower marital satisfaction. Additionally, the belief that one’s partner suspected them of cheating was similarly associated with lower relationship satisfaction. This highlights the significant role that trust and perception play in maintaining marital happiness.

“Believing that one’s partner has engaged in extramarital sex can be stressful, and one study of undergraduates in a romantic relationship, most of whom were in a dating relationship and all of whom either suspected their partner was cheating on them or had cheated on them in the past 3 months, found that the degree of suspicion about a partner’s infidelity was not only negatively associated with relationship satisfaction but also positively associated with depression, physical health symptoms, and risky health behavior (Weigel & Shrout, 2021),” the researchers explained.

“It may be that these types of psychological, physical, and behavioral factors contribute to lower relationship satisfaction for people who suspect that their partner is engaging in or has engaged in extramarital sex. The current study builds on this research, and to the best of our knowledge is the first study to include both members of married couples to examine the associations between both members’ history of extramarital sex and their beliefs about their partner’s history of extramarital sex and their own level of relationship satisfaction.”

The study, “‘I know what you did’: Associations between relationship satisfaction and reported and suspected extramarital sex,” was authored by Mark A. Whisman and Lizette Sanchez.