Great analogy with the burning down of the house... I've often wondered how my AH would have treated me if I ever did even one of the crappy things he's done to the girls and I. I've forgiven more in this lifetime than I can keep track of but if I lose my cool, cry, get angry etc.... you better believe I'm going to hear about my "crime" forever...
Like you said, I think whether he's reached his bottom or not, I have reached mine as it sounds you have reached yours with your W.
I'll tell you this-- my daughters are a lot more peaceful and calm and gentle with one another with my H being out of the house. It's the difference in terms of how kids seem when the A is out of the picture that really makes it clear there's a noticeable difference when he's gone...
How is your D doing?