I've asked her to stop using my bathroom. This triggers times that she would go into the bathroom and stay for 30mins while she was messaging the AP. I've asked her not to hang out in my bed or bedroom while being on her phone and then leaving at 9:00 to go into the other room. In the past she would do this and while in the room she would message him from 9:00 - 10:00.
Just remember to have a plan in case she decides to take a crap on you and not give you this space, because ultimately it's her house too and you can't lock her out.
Sunday just before my son and I were going to go to church she would not let him leave with me. She then took my car keys and would not let me leave either. She claims us attending church in our small town only helps further people talking about what has happened and it makes her look bad.
I hope you took your son and left. This is unacceptable to allow her to control you. Her looking bad is on her, you do what you want to do.
Issuing the ultimatum won't be as important as showing her something new.
H 34 W 29 BD 3/12/18 Divorce Busted Spring 19
It is not things that bother us, but the stories we tell ourselves about things.