The best thing to do is get off the crazy train. His continued attempts to explain, beg, point out happy times, fun memories... its one way to have control over your thoughts. He's using your sensitivity, compassion and heartstrings against you.

Disengage. Get off the crazy train and only look forward. The past is over and you can look back at it later, when you are back in full control of your reactions. Angry reactions to his behavior are a signal to him that he still has some control.