Read "parenting with love and logic". Lots of great ways to deal with parenting issues. When you are done, Give it to wife and say: "I read this and I liked the advise. Would you read it and give me your opinion?"
I picked this line up somewhere and it makes sense: "Who ever reacts emotionally first looses". Let the child react emotionally. Validate the emotions.
I used the "Draining my energy" statement a lot.
"This is starting to drain my energy, I might not have enough energy to _________"
The blank would be something important. "Take you to the birthday party this friday" starting this at 12 might be more difficult, but doable.
All I would have to say is "Do you want to drain my energy?" and the conflict would USUALLY de-escalate.
In your case, I like the baby sitter idea, but I don't know if it is a good idea RIGHT NOW to leave an unruly 12 yo child with a sitter. The child needs to fear the consequences her parent will give her for being unruly around a sitter.
Do as therapist says. get clarification and feedback next session.
Did you miss the movie? If so, then that is a BIG ENERGY DRAIN. My energy would be so low that I would not have any energy to anything the child requests until they raised my energy back up.
The cell phone is a great discipline. You and W need to be on the same page.
"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