Previous research has demonstrated the utility of men’s perceptions of their partner’s infidelity as a predictor of male sexual coercion in the context of an intimate relationship (Goetz and Shackelford, 2006 and Starratt, in press). Not all men who suspect partner infidelity are sexually coercive, however. Using reports secured from 280 men in a committed, sexual relationship with a woman, the current research provides preliminary evidence of a moderating effect of relative mate desirability in the relationship between perceptions of female infidelity and male sexual coercion. Specifically, men’s perceptions of their partner’s infidelity are positively related to men’s sexual coercion only in those relationships in which the man perceives that he is of equal or greater desirability than his partner. Men’s perceptions of their partner’s infidelity are not related to sexual coercion by men who perceive that they are less desirable than their partners. The discussion addresses interpretations of these findings, limitations of the current study, and directions for future research.