Partners often encounter situations in which their needs and preferences diverge. Partners sometimes prefer to be on their own and withdraw from interactions, and these situations can cause distress. We hypothesized that optimists may navigate such situations more adaptively. Using momentary assessment and questionnaire data from 103 couples, we examined how spouses responded to perceived partner withdrawal and whether optimism moderated these responses. When spouses perceived the partner to withdraw, they reported less positive and more negative behaviors. Optimism moderated this effect beyond the effects of positive expectations, suggesting that optimists are less reactive to withdrawal. Partners with more positive expectations reported more benevolent behaviors, although they reported less benevolent behaviors on days of partner withdrawal than on other days.