Are you sure you are over your childhood? You have put up with quite a bit. You might find Al-anon helpful and healing.
If your husband has starved you from physical intimacy, I can only imagine how much emotional intimacy you shared. When he spends money as he did for himself, what does it deprive you of?
You have a chance here for a better life. Do you want your son to think its okay to not respect his wife? Do you want him to grow up with a mother who is depressed? What will happen to you emotionally if you stay in this situation, and how will those emotions end up coming out and impacting your actions?
Sometimes its okay to let go. You are not abandoning your child. Your marriage has died, and your husband doesn't seem interested in it. I know you said never ever, but was that fair to yourself? You can't control your husbands actions. But you can control what you do, and set boundries. Set what feels like respect-- he can't call her, he has to do counseling, you have to have time set to work on marriage, no big spending without discussion, no yelling, whatever it means to you. And if he wont do it, then you know. He isn't interested in improving your marriage.
I had a husband who wouldnt go out with me, didn't want to spend time with me, spent wildly in order to find some sort of happiness or satisfaction, and a whole bunch of much nastier stuff. But I still felt like I needed some golden ticket for it to be okay. Now I wonder, why did I feel like I deserved so little? Why did I not feel I deserved basic respect in the relationship? Part of it was that I did not like the choices, I did like that I had no control over what happened, I felt sure that if I was nice and good he would snap out of it.
