This is a crazy-a$$ story. I am only saying that because I don't want you to forget it. I have my own crazy-a$$ story, and when I'd get sad and lonely, I'd try to rationalize it somehow. I hear a little of that, like "they only got married in their minds" and "I'd only take him back if..." Just stay focused on the facts - at best, this man you trusted and loved went on a bender and cheated on you with some bar hag.
You know, many of my relationships have ended in dramatic ways. I think that I was always unwilling to recognize red flags and unwilling to leave sketchy situations. So, my good old HP has had to step in many times to make it so that I had no choice but to leave. I can just imagine my HP shaking his head and rolling his eyes after showing me red flag after red flag, and then finally going, "OK, wonder if she'll leave if the guy if he has an affair with her friend!"