The current study tests an explanation inspired by social baseline theory (Beckes & Coan, 2011. Social baseline theory: The role of social proximity in emotion and economy of action. Social and Personality Psychology Compass, 5, 976–988. doi:10.1111/j.1751-9004.2011.00400) for the mixed blessings associated with received emotional support from one’s partner. We reason that the receipt of emotional support engenders benefits only up to individualized baseline points—that is, support effects will be nonmonotonic. In two dyadic daily-diary samples (N = 38/80 couples, over 21/35 days, respectively), we used piecewise multilevel modeling, finding support for our hypotheses. Receiving emotional support exceeding one’s baseline was associated with little affective change; receiving emotional support falling short of one’s baseline was consistently associated with worsened moods and relationship feelings. This work highlights the importance of individuals’ baseline levels as reference or comparison points for understanding support’s effects.