ggddjmdm,
I am so sorry you have to relieve that horror. If she's denying, there's every reason to believe the affair is ongoing--and you CANNOT cope with that addiction and alcohol dependence too. No one can.
You're going to need all the support you can get. Do you have friends, family, a trusted pastor to confide in? If your wife's OM is married, the best thing you can do is find out who she is, how to contact her and inform his wife about the affair. Scary, but that woman can be a huge help by putting pressure on the other side of the affair. Don't underestimate that. Read everything on this site about Plan A, but be forewarned that you CANNOT save a marriage while one partner is addicted to a substance.
I don't know what to tell you about that, but perhaps someone here who's had that complication will be able to help you. The weekends can be slow, so hang on.
Apart from that, all I can suggest is that you contact the Marriage Builders counseling center. I know, it's weird to get counseling from a site you've found on line, but I can assure you they are legit, and very very well versed. Get the number of the counseling center from the home page and set up an appointment with Steve Harley. For your $195, you will get straight, specific advice on how to proceed. He helped me in my desperation two years ago. Because I had NO idea what to do, I just trusted his advice. Everything he told me was counterintuitive. Would NEVER have thought of those things myself. But it worked out...we are well into our second year of reconciliation. In our sitch, it took a miracle. Sounds like you need one too.
I pray for your miracle.