Very rude MIL

My husband and I have been together for 6 years his mother has never liked me because he is the youngest and I "took him away" he is in the military and so she wrote him a letter telling him to leave me, she has called me many names, she ruined our wedding by buying the decorations without our say so, doing what ever she pleases with them an once we said enough is enough she told us we had to pay her 700$ for the decorations which fine we did well then I was a cunt for wanting my dress back from her family friend who had had it for MONTHS (my husband was going overseas and so was I, so I wanted my dress back so I didn't have to worry about it) well I was so horrible for that she called me screaming at me because I insulted her friend ( WAY more happened within our 6 years). Fast forward to most recent years that we have decided we do not want kids an so he is going to talk to his doctor about getting g a vasectomy because it is less invasive and I've been on birth control for our whole relationship we agreed that if later down the road we want kids then we would adopt. She has told his ENTIRE family about this and she has told them it's all me MAKIng him do this she said "she's making him do this he wants kids and she's being a selfish bitch" mind you if he wanted kids we simply would divorce because I do not. But surprise he doesn't either. I am really thinking about confronting her about this. He mentioned cutting ties with his family but that's his family I don't want him to just cut them off but she won't fucking stop. I've tried to talk to her an she just manipulates people till they shut up and take her abuse. Long story short would it be a bad idea to open the can of worms and confront her?

We did talk to her and she denied everything! Even though we have heard it from a handful of people.