Objective This study investigated the relationship between perceived mate value discrepancy (i.e., the difference between an individual's mate value and their partner's mate value) and perceived frequency of mate retention performed by an individual relative to his or her partner. Method In two studies, participants in long‐term, exclusive, sexual, heterosexual relationships reported their own, and their partner's, mate value and mate retention. Samples included 899 community members (Study 1) and 941 students and community members (Study 2). Results In Study 1, we documented that individuals with higher self‐perceived short‐term mate value, and who perceive their partner to have lower (vs. higher) short‐term mate value, perform less frequent Benefit‐Provisioning mate retention, controlling for the partner's Benefit‐Provisioning mate retention. In Study 2, we documented that individuals who perceive that they could less easily replace their partner, and who perceive their partner could more (vs. less) easily replace them, perform more frequent mate retention (Benefit‐Provisioning and Cost‐Inflicting), controlling for the partner's mate retention. Conclusion These results highlight the importance of assessing perceived discrepancies in mate value (notably, regarding the replaceability of self and partner with another long‐term mate) and perceived mate retention behaviors of self, relative to partner, between men and women in long‐term relationships.