"At least I tried." That is what is going to get you through this. I stayed with my stbx for four months while he continued to cheat on me because I felt that I needed to make sure that I did everything I could to save us. Thats how I felt I'd get through it without regrets. Marriages are partnership and eventually, the "partner" needs to get on board. If not, get out and take care of yourself. That is what you are doing now.
As for him regretting it... I'm sure he will, but you won't. You'll move on with your life and become ridiculously happy and he'll keep being the same jerk and never ever learn from his mistakes. He's on a downward spiral. Don't let him take it with you.
As for the bad day. It's okay to have those. It doesn't mean you're not making progress. You're allowed to have the bad days so go easy on yourself. Give yourself permission to pull the covers over your head and just cry it out. When you're done, get up, get moving and push forward. Happiness is a choice. You may have to choose it 30 times a day, but you can do it.
When you are happy as an individual, you are in a better position to determine whether a partner enhances your happy life or weighs it down.
