Well said. Writing what you feel can be so therapeutic. I wouldn't send it though, because if he's still actively drinking he won't take responsibility for what he did.
Hugs, I know how you feel. Especially this part:
A part of me died when you wouldn’t help me and I really needed it. A part of me died when you would fall asleep on the couch and my attempts to move you to bed with me didn’t work. A part of me died when you wouldn’t go out with me anywhere. A part of me died the day you stopped being affected by my tears and would just keep yelling through them. Yet, I forgave you over and over again because of love and because of commitment, but it got to be too much.