Following a breakup, people often indicate that they have lost part of themselves. The process of coping with such a loss involves rebuilding a sense of self without the former partner. The present research examines the effect of breakup on two aspects of identity, as well as the potential factors that may contribute to perceived change in identity. In Study 1, the Self-Assurance and Concern for Others (SACO) scale was developed to assess two aspects of identity thought to be susceptible to change following breakup. The scale correlated with established identity-related constructs in the expected direction demonstrating some validity. In Study 2, participants who experienced a breakup (N = 100), reported a decline in self-assurance, but not in concern for others. In Study 3, participants in relationships (N = 330) were assessed longitudinally. Results suggested that people who broke-up use self-enhancing techniques by derogating their pre-breakup self in an effort to cope with the threat inherent in the breakup. Whereas participants in Study 3 perceived changes in both self-assurance and concern for others, there was no significant group level pre- to post-breakup change in these aspects. However, when participants experienced genuine change following the breakup, they reported a decline in mood. In general, searching for meaning, and perceiving the breakup as central to one’s identity predicted perceived negative change in the self but not genuine change. The present research advances the literature on the perception of change in aspects of identity following breakups and advances method for assessing such change.