Ok CC, what about the finances, I understand that shes texting on "her own time", but are you paying her cell phone, or anything like that?
IMO, I dont think that you should demand an answer. I think that you should let her know, as I think you already have, that you will not live in an open marriage, that you think that her continued contact with OM is disrespectful to your M, and your family. And then stop all relationship talk. ALL relationship talk. Any timelines you set should be personal, dont set her up to lie to you or give her a warning of when you are going to act.
Even if you do demand answers, if there is an OM involved, she has this sort of fuzzy, warped view of what will happen when you and her go your seperate ways. She cant fully appreciate what it will mean... thats the whole idea of her being in a fog. She thinks that you are the obstacle to her happiness, and getting rid of you will free her up to be with OM.
I guess I gave the wrong finger to the wrong man...