the objective of the current research was to examine the potential influence of fertility status across the phases of the menstrual cycle (mc) on women’s romantic relationship dynamics. specifically, women’s feelings and perceptions of interpersonal closeness, relationship and sexual satisfaction, commitment, investment, extra-pair attraction, attitudes toward infidelity, and self-perceived mate value were examined. in order to carry out this study, 20 pair-bonded naturally cycling women and 32 pair-bonded women currently using some form of hormonal contraception (hc) from 阿根廷vs墨西哥竞猜 and the general community of thunder bay were recruited to take part in the “relationship satisfaction study.” a within-subjects design was used to examine significant changes across romantic relationship variables between a high fertile phase (i.e., periovulatory phase) and a low fertile phase (i.e., mid to late luteal phase) of the mc. during the periovulatory phase, naturally cycling women also used midstream urine test strips to confirm the presence or absence of ovulation. naturally cycling women were found to rate the appeal of alternative dating/relationship partners as significantly greater (i.e., greater extra-pair attraction) during the periovulatory phase; however, this only occurred for women who reported that their partners were lower in mate value. moreover, a significant main effect of mc phase on self-perceived mate value was discovered, such that naturally cycling women during the periovulatory phase rated themselves as more desirable than during the mid to late luteal phase. these results are consistent with previous research regarding women’s dual mating strategies and further contributes to our knowledge regarding purported hormonally-mediated mc phase shifts in the context of romantic relationships.