I strongly dislike my mother in law

Time for a rant, advice or commiseration welcome.

My mil is kind of a bitch. Not kind of, she is. She is like a middle school girl who fishes for stories and ammunition to use against you in the future, she talks about people behind their backs, she tries to pit my husband against me, she guilts him into stuff and whines like no other, and she implies that if you don't agree with her or do something her way you are WRONG. She tried to disclude her own husband from Christmas dinner because he had to do something else during the day so she tried to ensure he had to eat leftovers instead of eating with the whole family just out of spite.

I can't stand her in my house and if it were up to me she wouldn't be welcome in my house.

I am worried that when I have a child she will cross the line and not respect my boundaries but my attempts to set reasonable boundaries now make her throw pouty tantrums.

I know this is going to end badly one day and if it weren't for my husband she wouldn't be in my life, but now I get to find a way to deal with her. Seriously can't stand her.