A friend and I had a disagreement, should I still attend their wedding in a few weeks?

A close friend (old roommate, groomsman in my wedding, 15 years hanging out) and I had an argument a few weeks ago. He feels I went against my word and let he and his new lady down.

Since then he’s been all business and passive aggressive towards me when we have to interact. Not rude, just cold. I tried to address it directly but we just disagree and he’s hurt. I get that.

I’ve opted out on the bachelor party, but feel missing his wedding would be a “big deal” and mark the end of a friendship. At the same time, I don’t want to be rude by showing up and causing any grief for him or his fiancee.

Right now I’m planning on attending and just feeling it out. I’ll know about half the people at the wedding, can leave after the ceremony, and want them both to know I wish them well.

Am I out of line on this? Is it worse to miss the wedding or show up and possibly be a negative on their big day?

What would you do and why?