The only suggestion I have is to no longer discuss OM or what the C says with your wife (in terms of the children meeting the OM, your W is aware of how everybody feels and chose not to respect the feelings of the father of her children and a trained C). You made the call a few days ago to let her know you were not pleased so she is aware of your feelings. Any other talk about it with your W will only result in further justification by her and/or an attempt to draw you back to being "old Kevin" who will always let everything slide.
If she asks to speak to you in private I might give her one of the following responses:
Is it about the kids or money?
I really need to run, please go ahead and e-mail me and I will get back to you when I am able.
W, I made my feelings very clear about the OM and the children when I called you the other day. I have decided not to engage in further conversation about the matter.