I examined negative shifts in past self perceptions after a romantic breakup (i.e., toward thinking one's pre-breakup self was not as happy and not as positive of a version of themself as they thought at the time) as a means of preserving post-breakup well-being. I recruited 184 people who were in romantic relationships to complete satisfaction and self-related measures twice, four months apart (retrospectively at Time 2). Those who experienced a breakup between ratings indicated larger negative shifts in past self perceptions than those whose relationships remained intact and larger shifts were associated with greater post-breakup well-being. Secondary analyses suggested that these shifts may improve well-being in part by helping one disentangle their ex-partner from their self-concept. The results were inconclusive (due to methodological limitations) regarding whether they also do so by ameliorating emotional distress. Implications, limitations, and suggestions for future research are discussed.