WW in PA: Threaten to tell kids? Confront OM?

[hoosjim]

LBH here, bomb dropped three months ago (January 2016) after I discovered phone/text records and overheard call.
Affair (EA)with OM is now approximately 6 months old.

W "drew back" from affair for a handful of weeks but now fully "engaged" with OM yet again.
I have successfully implemented GAL measures (which have been noticed), but W speaking out both sides of her mouth.
Says she is "not in love" does not "Want to be with anyone" and relationship with OM is on hold, but I recently discovered this is not so and that she is telling him how much she wants to be with him, is "working on" breaking free from me, etc.
Two children, older teenagers, and her fear of losing/alienating them are probably only reason she is currently sticking around, IMO, based on things she has said.
Also, overheard conversation and way she talked/acted (like a completely different person from the woman I know and married--very vulgar/bawdy, etc.) make me think she is probably what Sandi would designate as a WW... if not for the fact that the affair has still not gone physical (although phone sex has, I think, possibly been involved.)
She is still living in the house and in our bedroom, though we are not having sex.
The background to our difficulties involves multiple years of neglect (7-10) on my part as the primary culprit.

My question is, at what point (possibly now) do I put my foot down and say "Enough is enough-- I can let you go if I have to but I will not share you. Either you cut contact with the OM or we move you out-- of the bedroom if not the entire house.")
Too late for this to have any effect? Too soon for the circumstances?

Curious.