Involvement in an extramarital affair can have serious consequences for the partici­pants, including loss of self-respect, severe guilt, stress associated with leading a secret life, damage to reputation, loss of love, and complications of sexually transmitted infec­tions. The dynamics of the secrecy typically have damaging effects on the quality of the couple’s relationship. The secrecy and lying (even by omission) erode the connec­tion between spouses and amplify emotional intensity and the illusion of closeness to the affair partner. Frank Pittman, author of Private Lies: Infidelity and the Betrayal of Intimacy, maintains that a person becomes more distant from whomever he or she lies to, and closer to whomever he or she tells the truth to (Pittman, 1990). Researchers examined secrecy in relationships and found that subjects spent more time thinking about former lovers who were kept secret than about those whom their current partner knew about (Wegner et al., 1994). The researchers also set up a laboratory experiment involving male and female university students. Subjects were seated in mixed-sex pairs for card games, and couples were asked to touch feet under the table while playing cards with another couple. Sometimes this game of footsie was secret; at other times it was not. Couples in the "secret footsie" group reported greater attraction to each other after the game than did couples whose foot touching was not secret.

Research finds that marriages usually fare better when an unfaithful spouse proac­tively discloses an affair to the other spouse than when the other spouse discovers it on his or her own (Aaronson, 2005). Regardless of how a betrayed spouse finds out about infidelity, he or she often feels devastated. The betrayed spouse can experience a variety of emotions, including feelings of inadequacy and rejection, extreme anger, resentment, shame, and jealousy.

Research has found that in heterosexual couples, men are more likely to believe their female partners would have an emotional affair, and women believe their male partners are more likely to have an affair for the sake of the sex. Psychological distress for both men and women was greater if their partners had affairs that violated their expectations. More women were distressed by imagining a partner falling in love with someone else; in contrast, imagining a partner having sex distresses more men than women (Cramer et al., 2008).

Divorced individuals often mention extramarital relationships as a cause of their breakup. However, the discovery of infidelity does not necessarily end a marriage or ultimately erode the quality of a marriage. In some cases such a crisis is beneficial, in that it motivates a couple to search for, and attempt to resolve, sources of discord in the relationship—a process that can ultimately lead to an improved marriage (Kalb, 2006).