Here is my last question: we live under the same roof. I really don't know how to be "sort of friendly, but living my life?" Suggestions on how to do this?
Treat him like a brother. Right now you are unhappy with him. I don't think friendly it the term. More like a how you would interact with a waiter.
You project that YOU ARE HAPPY.
Do not argue with him.
If he treats you with disrespect, leave the room.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712
