While you certainly seem to have your list of issues regarding your wife, I would imagine that she has some of her own related to you. It's hard being married to someone with an addiction problem.
Re: your most recent affair . . . of course it was fabulous. You and your friend got to have fun and laugh because you didn't have to deal with any real life issues together. I would bet that the tenure of that relationship would change if you were raising kids/sharing finances/living together. That's so not fair to your wife, no matter how "harsh" she is. End it if you're not happy. Then, look for the person you want to be with.
Getting sober should be your first priority, then, figuring out whether or not you want to remain in your marriage.