I don't know, that response kind of makes it sound like you're chastising a child. She's not a child. She's a grown woman who is capable of making her own choices.
What you want to do is set a firm boundary. You want to save your marriage. If she wants to save your marriage, too, OM HAS to be out of the picture. She cannot focus on your R with her mind clouded by continuing contact with him. So, as far as you're concerned, there's no working on the R until she's done with him. Anything else is disrespectful to your M and to you.
