In you mind, go back to that fateful day and slap the living shit out of him. Seriously. I think I know what you are talking about. Personally for me, it's my parents disowning me and the way they treated me that ruins almost all of the few childhood memories I can actually remember.
Sometimes I go back in my mind to the day my dad talked to JWs for the first time. In my time travel fantasy I hug my dad and tearfully beg him to throw away the magazines he got that day, then I punch him right in the nuts...
I'm sorry you have to experience this. I think you should look for a good counselor. They might be able to suggest some coping strategies that will help. Mine was off the cuff and I didn't mean to make light of you situation.
TB-