People in close relationships can, and often do, experience ambivalence (i.e., mixed feelings) toward their romantic partner. Although ambivalence is common and consequential, research on this phenomenon is fragmented. The present work examines how four different types of ambivalence (i.e., objective, subjective, implicit-explicit, and implicit ambivalence) relate to well-being. In four intensive studies (N = 1,134) and internal meta-analyses, ambivalence was related to lower personal and relational well-being, but this association was only statistically significant for explicit (i.e., objective and subjective) types of ambivalence, with subjective ambivalence showing the strongest association, particularly for relationship outcomes. This work is the first systematic study of ambivalence and well-being in relationships and highlights the importance of capturing mixed feelings in relationship research and how such focus can benefit research on attitudinal ambivalence and well-being more broadly.