I guess I should add this in, don't criticize the OM. You can acknowledge to her that violating a private home isn't showing a great deal of maturity and you hope he realizes that.
But don't attack him outright, criticize the behaviour gently and briefly and let it go.
If you attack the OM and point fingers there, she's turned you into a Jealous child and you have given her more reason to leave.
Be an ADULT and she can't criticize you. She will have nowhere to go but back to you. Be an adult and she will change her mind.
Your posts here don't sound very adultlike, and that's ok, rant here, but don't behave like you are here when you are with her. I would reccomend you practice HERE how you would deal with her.
SHow maturity. She won't have anything to criticize but your past. And she will let that go in time.