Doug,
I just read your thread today, and I'm sorry to hear you've been going through a bad time. It's awful to love and marry someone only to discover what they're truly like. Adultery's a distateful thing to do when you're in a relationship.
I'm glad you took Liza's advice. I hope you'll continue with therapy. And in time, you'll come to an conclusion and decide on which road to go on.
Take care of yourself.