Am I the arthole for not attending my sister's wedding because she didn't invite my partner?

So my 29 female, sister 27 female, is getting married in a few months.

We've always had a decent relationship, but we've never

been super close. I've been with my partner, 31 male, for four years now, and we live together.

My family knows him well and he's come to many family gatherings years. When I received my

wedding invitation, I noticed it was only addressed to me. I asked my sister if my partner's invitation got lost in the mail.

And she said she didn't invite him because she wanted a small, intimate wedding with just close family and friends.

I pointed out that my partner is practically family and that other relatives are bringing their significant others.

She replied that it's her wedding and she gets to

choose who attends. I was hurt by this and told her that if my partner isn't welcome, then I won't

be attending either. She got upset saying that I'm being selfish and that I'm putting my relationship

over our family. My parents think I should just go to keep the peace, but I feel strongly about standing up for my partner and our relationship.

Am I the asshole for refusing to go to my sister's wedding if my partner isn't invited?

You should just go, Jared, but it's tight after.

I don't think you shouldn't go.

Yeah.

But you should definitely go just to, you know, keep the peace because you might end up with great and not going.

Yeah.

Because what if you break up with this partner now?

Yeah.

Do you know I overheard the other day I was going, we were at the studio and I was going to

test go and buy like drink or something and there was a couple behind me and I guess they're

...