If you can actually find the strength to leave, I urge you to do so and not look back. I'm in a similar situation but I finally left not too long ago, only to turn around and go back under the naive belief that he would be different. Trust me, he won't change. He may do things temporarily to make you believe that changes are being made and to make you think there is enough progress on his end to give you hope. Don't fall for it. I know that leaving is the hardest part, but if you can manage that, you'll end up just fine.