ObjectiveThis study aimed to examine the effects of promotion focus on the relationship between high mate value discrepancy (MVD) and marital satisfaction and alternative monitoring behavior.BackgroundMuch research has documented the detrimental effects of MVD on marriage. Nevertheless, little work has been devoted to investigating the individual differences within the negative relationship between MVD and marital outcomes.MethodIn all, 700 Korean participants (350 men and 350 women) were recruited for an online survey. The moderating effects of promotion focus on the relationship between MVD and (a) marital satisfaction and (b) alternative monitoring were tested. We computed MVD with three methodologies: absolute difference, weighted difference, and residual score.ResultsWhen confronted with a high MVD, highly promotion‐focused individuals were shown to maintain a more satisfactory marriage than did those low in promotion focus. At the same time, however, highly promotion‐focused individuals showed a greater tendency to engage in alternative monitoring behavior under high MVD.ConclusionPromotion focus could buffer the negative effects of MVD on marital satisfaction, but it could also exacerbate the detrimental effects of MVD on alternative monitoring behavior.ImplicationsUnderstanding one of the underlying reasons on seeking alternative romantic partners and how individuals differ in their chronic ways to be motivated can help counselors and family practitioners. The information helps tailor strategies to meet specific goals and directions that individuals have. This may, therefore, better guide couples to adjust their marital lives.