Stand up to her. You can do it! Who cares if she fights about it every time? She always will if she gets her way every time.
My WW is a bulldog. She bullies her mom, she bullies her SIL, she bullied her XH, she bullies her friends, co workers, etc... Do you know who she doesn't bully? Her Dad and now I, no longer. Why? Because her dad has never put up with her $hit and actually abused her as a child. This is definitely not a good thing but she knows she won't get away with it with him. And now me because I created boundaries and I no longer tolerate it. I stopped caring about her reaction when she doesn't get her way. For example- a couple months ago she was very disrespectful to me. I stated "I will no longer tolerate you or anyone else speaking to me like this" and I walked away. I had to re-enforce this boundary over and over again. Not verbally most of the time. I would just put my headphones in and walk away. A couple days ago she began insulting me in a conversation. I calmly stood up, said "my half of this conversation is over." and I left the room. She spewed some more $hit at me but I just kept going and left the house. About 20 min later she sent me a text that said " I'm sorry for being a jerk" I didn't reply but this is a huge step in the right direction for her and our R. Whatever that relationship ends up being I will not tolerate her $hit any more and she knows it.
You can stand up to her and it's worth it. You've allowed her to act the way she does. Allowing it enables it. It's a habit. Habits are hard to break but you can.
Me 40 WW 41 D 4 S 12 S 14 BD 6.16.2015 W stopped wearing ring 9.4.15 W Filed Divorce 9.14.15 My ring off 11.15.15 D finalized 12.18.15 WXW (wayward X wife) moved out 1.28.16 got her own place