Z, You will eventually need to tell her how her actions are causing you pain. You will eventually need to tell her to pick.
You need to decide when that time is. I did it early in my crisis. I even confronted two potential OM's.
The best way to do it is to tell her in a non-confrontational manner what you know. Then make it clear that she is making her own choices which do not appear to include salvaging the R.
If she is playing the EA game with OM, it may be better to urge her to leave at this point.
