Sisters wedding - am I in the wrong or her?

hi everyone!

not baby related at all but wanted some neutral advice really.

i have been with my fiancé 13 years and we have 2 bhsren together. My sister and fiancé have generally got on well but have had the occasional trivial disagreements over the years but always made friends again. 3 years ago they had a massive bust up. Basically I thought my fiancé had been cheating on me and during an argument with him at home I called my sister to help me get him out of the house. They ended up having the biggest argument ever, she went to hit him, he called the police it was a nightmare! The police Came and left and that was the end of it. Turns out he Wasn’t cheating at all and every member of my family can see that apart from my sister. Since that day she has decided she never wants to see him again As he nearly got her arrested (he didn’t he just called the police and she got a warning to Calm down and not tth and hit ppl). I thought time would pass and she would get over herself but it’s just got worse. I used to look after her son one day at week put she started paying for him to go to nursery instead just so my fiancé couldn’t see him. She has since got engaged herself and had a party or that and a 30th bday party and although I’ve been invited she won’t invite my fiancé. ive Made it quite clear from the start that my fiancé is my family and he has been In the family 13 years so if he isn’t invited then neither am I. She doesn’t care and would rather not have me there either then spend a few hours in his company for family occasions. My parents are devistated by this as they can no longer have us both for Christmas.

My sisters wedding is now 6 months away and again only I was invited. She sent me a text asking if she should bother sending an invite to me. I told her I won’t be coming without him aNd how upset I was as I feel like she is making me choose and she hates him more than she loves me. She completely lost her shit and blocked me for about a month just for saying that!! She’s got over herself now and unblocked me and said at least we know where we stand from now on and won’t be attending each other’s occasions in future. 

So I guess what I’m asking is. Am I right? I’ve kept this going for 3 years now and refuse to attend anywhere I feel my fiancé should be too. it Breaks my heart as we have children of sim age that barely see each other now and I’m so angry with her that she doesn’t see the bigger implications of her stubbornnesS. The children and our parents are really suffering, as well as me. 

Also just as a final note my fiancé is more than happy to apologise to her as he hates seeing what this is doing to me And how upset I’ve been. I’m so sad that I’m gonna miss her big day but I feel I have to stick to my guns. 

ANY advice welcome 🙏