There is really nothing more besides contacting the OM's parents that you can do now. The chickens will be coming home to roost for her soon. It will dawn on her soon that this whole thing with a married man 10 yrs her senior and fellow officer was doomed from the start. It'll all come crashing down on her.

These are the times when I try to say a prayer and ask God to take control and do whatever is his will. Stick with Plan A, and try to relax and breathe. You can't force her to see the light. It will have to happen on its own over time with you being the constant safe place to land.