The impact of one’s role in a relationship when defining infidelity

This study examined whether individuals' definitions of infidelity differ based on perspective —evaluating their own behaviors versus their partner's identical behaviors — to test for the presence of self-serving bias in infidelity judgments. A nationally representative sample of 205 participants completed an online survey through Qualtrics. Participants were randomly assigned to evaluate potentially unfaithful behaviors from either a self-perspective ("You are exchanging inappropriate texts") or partner-perspective ("Your partner is exchanging inappropriate texts"). Behaviors were categorized into five factors through principal components analysis: active cheating, infatuation, social activities, fantasy, and discussion of sex life. Ratings were made on a 7-point scale from "definitely not cheating" to "definitely cheating." Independent-samples t-tests revealed significant perspective differences for three behavioral categories. As hypothesized, participants judged themselves more leniently than their partners for active cheating (p < .05) and social activities (p < .05). Unexpectedly, participants rated their own inappropriate discussion of sex life more severely than their partner's identical behavior (p < .001). No perspective differences emerged for infatuation or fantasy behaviors. Sex differences were found for active cheating and fantasy factors, with females rating behaviors as more unfaithful than males, but biological sex did not interact with perspective effects. Results provide mixed support for self-serving bias in infidelity judgments, suggesting that perspective-taking effects vary by behavior type. The reversal for discussing sex life may reflect unique concerns about violating partner privacy. These findings highlight the importance of explicit communication about relationship boundaries and have implications for couples therapy interventions addressing infidelity-related issues.