I'm so sorry you're going through this, cm87. I feel for you. I was like your wife for about 6 years and it killed my marriage and drove me into a deep depression. She's not going to quit unless she wants to. By the time I did it was too late to save my marriage. Go to Al-anon, it helps you gain a more rational and detached understanding of the situation and your role in the relationship.
Good luck to you.