What jumps out at me is the effect it is having on your daughter. Are you afraid of what will happen to her if you stay?
Taking the focus off of him (and losing the idea that I knew what would actually be heartbreakingly drastic to him) really helped me separate myself from AH.
Do you attend Al-Anon? That could be particularly helpful, whether you decide to stay or go, as well as Alateen for your daughter. My heart breaks for her.