I don't feel you should stay together for the kids, I feel you should make it work for the kids. But even of there were no kids involved I would still be here wanting to make my M work because I love my husband. .
THIS IS POWERFUL!! You are right and I pray that you'll husband will realize how valuable you are and that you will show him that you can and will make changes. Let him know how you are working on your issues and let him see results. I think a lot of this is HIM, and he's probably really conflicted right now, but he's missing out on a lot, a wife and daughter who love him and need him.