Because she has been like this for 21 years and I don't trust her as far as I can throw her!
True that past behavior is the best predictor of future behavior. I am sure she predicts your future behavior based off your past behavior, but you are changing. This will confuse her. You drop the rope and it is no longer "Fun" for her to pull on it.
Anyway, humans are emotional creatures. Woman typically more than men. It is our job as men not to be "afraid" by a woman's emotions. Just understand how to read them. Reflect them back in word.
"You look angry"
"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