Long Rant.... really need some advice

32 weeks pregnant and just the thought of my SIL stresses me out. She is nothing but drama, at first we used to get along just fine I included her in just about every aspect of my pregnancy. It all went down hill when I expressed my rules as far as visitors go, that’s when things started to take a turn. I compromised with my SO that since I would have my mother and sister around because we live together I would allow my MIL and her as my SIL to be around for two weeks that we were restricting visitors. I asked for her opinion on it she said yeah sounds good.

Then 3 weeks went by started plan a baby shower, my sister ended up just doing the entire thing by herself because she felt she was not wanted in the planning of baby shower since we moved the date to January instead of late February, so she then decided that she was just gonna throw her own when I was further along. My SO and mother made the call on having an early baby shower so I was confused and angry when it somehow be some my fault and tried to say that I didn’t want her to be a part of anything. We also waited for her to contact my sister so they can plan together since she decided she wanted to do it after all waited 2 weeks and nothing was heard from her so my sister moved on on her own.

Fastward i tried to explain to her what the situation was she made it seem like it was fine and she understood, however that was not the case cause it was not long after when she decided that she no longer wanted to be involved in the insuring since the other two sisters would not be able to and since I’m excluding people she didn’t want to be there either she then told everyone on her side that I’m trying to push them away and don’t want them to be a part of anything which in turn made my MIL say she didn’t want to come around either. I suspected that from her since the youngest wouldn’t be able to come bc that just how they are. If she can’t be involved in something then they rather not be either which is childish that they base their attending to things based on wether or not their 17 yr old will throw a tantrum over it.

Weeks past and I still tried to be cordial and nice for the sake of my SO and my baby on the way. When she then took it out of hand and called me out my name texted my SO saying I was manipulative,drama, a hypocrite and that she was just going to keep her distance and that she only cares for him and my baby. I tried to make amends and confronted her about this for the sake of my SO since he doesn’t want our daughter around family nonsense. And it got no where she could not explain to my face how I was all these things or what I’ve done to her instead she went in circles about how ni pregnancy women she knows has ever acted the way I have through my pregnancy and neither has she and she has 3 kids.

I just said okay, and she went in as if everything was okay. She clearly showed it wasn’t bc she didn’t bother to show for Christmas until I was just about to leave. Showed up to my baby shower 5 hrs late then didn’t bother to acknowledge I was there until her brother came out.

Now I just don’t want her around at all and idk how to tell my SO without him being dismissive about my feelings or for I guess me to just “get over it” or her creating more unnecessary drama with the rest of her immediate family.

Long post sorry.