Making Peace with Moral Imperfection

How can we rationally make peace with our past moral failings, while committing to avoid similar mistakes in the future? Is it because we cannot do anything about the past, while the future is still open? Or is it that regret for our past mistakes is psychologically harmful, and we need to forgive ourselves in order to be able to move on? Or is it because moral mistakes enable our moral growth? I argue that these and other answers do not properly resolve the problem of temporal asymmetry in our attitudes toward moral imperfection, and I defend an alternative response, centered on our personal attachments and our biographical identity.