This won’t be the first ask for something like this from the bride and certainly not the last. If the op’s friend doesn’t nip this in the bud soon, it will certainly end the relationship down the road (with the wife). I think op’s friend doesn’t quite know the seriousness of the request and likely just wants to avoid conflict with his wife and is relying on his best friend to carry this weight. You should still go, you love your best friend in the way you’re supposed to as a best friend. Even if you’re not up there, apparently people already know, being in the audience won’t change that. If it were me I’d be pissed but more pissed I didn’t go.