"I don't see anything that I can do in that regard."
Yes you can. At the very least there needs to be transparency. She can write a letter to him and cc you on it specifically stating that you know about the A and that the two of you have decided to work things out. So any correspondences between the two of them will be made public to you.
If your W laughs at that and refuses to, then you have your answer. She's thinking more about herself than you. At that point, you tell her that it was extremely selfish, hurtful and disrespectful what she did and that if she can't understand that, then she needs to leave.
Does the OM know that you know what happened? What kind of business are they in?
That I can do. I'm not sure if he knows or not. I will find out.
