In recent years I have tried to become extremely honest with myself and my own accountability for failed relationships. You mentioned putting down others - I recently noticed a similar trend in my own past, not outright insults but the way I viewed much of the world was through cynicism and negativity, for example I had a sarcastic sense of humor. This was a very powerful realization for me and as obvious as it might seem to identify it wasn't clear because it was such an automatic thought process.
Did you feel the need to confront others in order to fix your emotional past?