I appreciate the suggestion, Finah, but I don't think that I will take that route. To me, "exposing" seems a lot like pursuing. You want the R with OM to end, so you try to introduce pressure through social channels. In my sitch, I would think that it would only backfire. No, my approach will just be clean, cold darkness. It is one of the greatest 180s that I could possibly choose to make. Plus, I want to have as little to do with my W at this point as possible. I can't takes it no more.
In addition, her family already knows that she's living with this guy, and I'm pretty dang sure that they don't approve of it. If her own family couldn't do anything to talk her out of it, I doubt anybody else would, either. The only person who can make such a decision is her.