Why do sacrifices undertaken in pursuit of approach and avoidance goals differentially influence well‐being and relationship quality? A cross‐sectional study (Study 1), an experiment (Study 2), and a 2‐week daily experience study (Study 3) demonstrate that the personal and interpersonal outcomes of approach and avoidance sacrifice goals in dating and married relationships are mediated by felt authenticity. When people sacrificed for approach goals such as to make their partner happy, they felt more authentic, in turn contributing to greater personal and relationship well‐being. However, when they sacrificed for avoidance goals such as to avoid conflict, they felt less authentic, in turn detracting from personal and relationship well‐being. Implications for research and theory on motivational processes in close relationships are discussed.