Conflicting parties experience threats to both their agency and morality, but the experience of agency-threat exerts more influence on their behavior, leading to relationship-destructive tendencies. Whereas high-commitment relationships facilitate constructive tendencies despite the conflict, we theorized that in low-commitment relationships, affirming the adversary’s agency is a prerequisite for facilitating more constructive tendencies. Focusing on sibling conflicts, Study 1 found that when commitment was low (rather than high), agency-affirmation increased participants’ constructive tendencies toward their brother/sister compared with a control/no-affirmation condition. A corresponding morality-affirmation did not affect participants’ tendencies. Study 2 replicated these results in workplace conflicts and further found that the positive effect of agency-affirmation in low-commitment relationships was mediated by participants’ wish to restore their morality. Study 3 induced a conflict between lab participants and manipulated their commitment. Again, in the low- (rather than high-) commitment condition, agency-affirmation increased participants’ wish to restore their morality, leading to constructive behavior.