Sorry to hear this 3kids. I have no answer for you regarding the the OM staying at your old house. However, you have every right in the world to approach your W about the OM driving your kids to school sporting events.
Seems like you have a lot of anger right now. When I feel this way I take a drive to a secluded spot and then I yell and scream everything I want to say "at" my W. Cuss words and all. I mean I really let it rip. Release that anger. After that I feel much more calm and I am able to carry out a civil conversation.
I hope that helps.
M42 W40 T17 M15 S13 S11 BD 7-14 A discovered 7-14 WAW moved out 10-3-14 D final 2-23-15