I know you sound like you have made up your mind about this but I hope you re-consider. IMO at this point it's not about you, it's about your friend. You have been honest with him. He will probably need you in the future. Your presence at his wedding may mean more than you will ever know.
Just when I thought I had everything figured out, you plant some doubt in the very back of my mind... or maybe it was already there.
Perhaps I am just being selfish. Perhaps I am upset that my concern for him was met with indifference. He asked for my straightforward, unvarnished opinion, and I really gave it to him. I was surprised when he responded with subtle gratitude, and once more when everything stayed exactly the same.
Do I really think refusing would make him reconsider? Would I be doing it because he deserves a best man who supports his decision or in retaliation for having chosen to marry this miserable woman after every friend he has told him to run? Assuming his mind is made up, no one else supports his decision, and I'm above doing something like that, it seems like there is much more to lose than there is to gain by refusing.
I think you should think of what you want as an end result. Best and worst case scenarios. In the end, you have to live with yourself.
I was in similar shoes a few years ago. My good friend was dating
a total jerk. We'd been friends for a long time and had witnessed each other in many relationships
. I knew how awful and unhappy her parents' marriage was and she and I had discussed their personality types and why they weren't compatible. Here she was reenacting the exact same scene. I had been there to pick up the pieces of her bad relationships
many times. I just couldn't do it again. It was like watching a train wreck. I wanted to warn her, but I also really didn't want to be there listening to every single sob story after their union because I had already listened to all her sob stories before and had endured all her lows in her relationship
with him. I decided that it was better to be honest with her and risk losing her friendship permanently than to let her marry him and be miserable. I felt like I was allowing a gigantic mistake to happen if I didn't say anything, although I knew that I had no business saying anything. I told her that I felt she was settling and my opinion was that even though I was sure she could find someone better, it would be better to be alone for the rest of her life if that's what she was afraid of, than it would be to marry him. She chose him as was her decision to make. Our friendship ended and *I* didn't have to suffer anymore listening to her awful tales about how he put her down, insulted her or treated her like crap yet again. I know she married him. I don't know if they're happy or not. I hope I was wrong about what I predicted for their marriage. I hope she's happy. But I am glad that I told her what I thought and I'd make the same decision again.
Contrast that with my husband. His best friend was like your friend. He'd never dated anyone. His wife had never dated anyone. They were set up by friends on a blind date. My DH and the groom's mom both
told him before the wedding that he was making a mistake. The groom said he feared he'd never find anyone else willing to marry him (which is sad, because I'm certain quite a few women would have been happy to marry him). My DH was his best man, even though he told him how he felt. The couple is still married 15 years later. They're clearly miserable. The guy often tells my DH how miserable he is but he doesn't believe in divorce. But at least, I get along with his wife (they're just not happy, but I think they're both nice people) and at least we still get together once in a blue moon as couples to hang out.
I think there's no correct answer across the board. You have to do what you can live with and what you will regret the least.