The pain stopped for me when I realized I didn't particularly like him whether he was drunk or sober, and had no expectations of him being able to meet my needs - he didn't have it to give. I realized I was going to leave when I saw the depth of his deceitfulness and his compulsion to control me. I also realized I wasn't going to fulfill his fantasy of being the "perfect" woman. Shucks, I went and made the fatal mistake in his eyes of being a flawed human being.
I knew I would leave when the anger gave way to annoyance and a feeling of dread having to be in the same house with him. Bottom line: I like who I am, and I like my life more without him than with him.
Barring some miraculous recovery on his part (which I don't logically forsee as happening), I am prepared to leave him when I graduate from college and get a job. If I decide to leave prior to my December graduation, I have a plan in place to do so.