WIBTA for refusing to attend my best friend’s wedding because my partner wasn’t also invited?

So, my (28F) best friend Sophie (27F) is getting married to her boyfriend Jeff (30M).

Sophie and I grew up in the same neighborhood and went to school together. About 3 years ago, I moved interstate after getting a great job opportunity. So I don’t see her much nowadays, though we speak on the phone or via Facetime at least once per week.

I was thrilled to hear the news about the wedding, particularly as Sophie hadn’t always had a good run with men. She had only been dating her fiancé Jeff for about six months, but that was about 5 months longer than anyone else!

However, when I received the invitation, the trouble began.

I’ve been in a committed relationship for over two years and live with my partner, Craig (32M). He is an important part of my life. But as we live interstate, Sophie is yet to meet him.

The invitation was for me only. It even had a note at the bottom that said, “Due to limited numbers, Invitations are strictly for those named.”

I reached out to my friend, expressing my disappointment and asking if I could bring my partner along, but they were firm in their decision to limit the guest list to individuals named on the invitations.

Sophie told me because she’d never even met Craig and that we weren’t married, she didn’t want to have fly-by-nighters attending the biggest day of her life and appearing in wedding photos that would last forever.

I told her that I’d been in a relationship – and living with – my partner – well before she’d even met Jeff, that I bet my relationship would last longer than her marriage anyway, and that suggesting he was a ‘fly-by-nighter’ was rude.

She didn’t take that well, and I maybe went overboard, but I’m genuinely upset. I know from other friends that there will be over 150 people there (Sophie doesn’t even have that many friends), so they’re not making it small and intimate with just a handful of close friends and family or anything.

I’m now contemplating not attending the wedding at all.

Am I being an AH? Should I put aside my feelings and attend the wedding solo to support my best friend, or is it reasonable for me to skip the event to make a point about inclusivity?