The purpose of this study was to examine whether codependency would mediate the relationship between self-differentiation and life satisfaction in married couples using the Actor-Partner Interdependence Model (APIM). A total of 447 married couples participated in an online survey, and the analysis yielded the following results. First, there were significant differences between husbands and wives in terms of self-differentiation and codependency. Husbands exhibited higher levels of self-differentiation than their wives, whereas wives showed higher levels of codependency than their husbands. Second, the actor and partner effects of self-differentiation on life satisfaction were not significant for either husbands or wives. Third, the actor effect of self-differentiation on codependency was significant for both husbands and wives, while the partner effect was not significant. Fourth, the effects of codependency on life satisfaction varied by gender. While neither the actor nor the partner effects of codependency were significant for husbands, both effects were significant for wives. Fifth, the mediating effect of codependency in the relationship between self-differentiation and life satisfaction was significant only for wives. This suggests that wives' self-differentiation and codependency have a greater impact on marital life satisfaction than those of husbands. Finally, based on these findings, we discuss the implications of this study and provide suggestions for future research.
