Ohmygosh. I'm sorry to hear about this turn of events. I'm really surprised to hear that, after spending so much time on this site and in the poly community, he feels like DADT and getting involved with cheaters is the way to go. I guess he's going through a lot right now. :/ I will be hoping for the best for you both.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.