I don't think it always works out to where you WILL get to a place where you're done. Some people live their whole lives in this misery. Some people never get a chance to leave their alcoholic/addict, because the alcoholic/addict leaves them.
I think for people who do leave, they can look back and see, yep, I was just done.
I hope you do leave, because that sounds like no kind of life. You're probably not doing him any favors by staying with him either. You're most likely cushioning any rock bottom he needs to hit.