Will Baude receives a letter from a divorced fellow on the subject of being left at the altar (Will's correspondent would have preferred it). I wholeheartedly agree that the time to leave is before exchanging vows, but the time to do so is not while all are assembled and waiting, but before, so the wedding itself can be delicately cancelled and the groom's agony is not drawn out by forced participation in what was to be a happy gathering (while Miss Manners may think that the party will simply go on with more spice, the party is certainly over for the groom, and I don't think that the gossipy good times of the guests are a deciding factor for him).
I wish to highlight the actual hypothetical at issue, however: this is a choice between abandonment at the altar, before all and sundry, or an immediate annulment or divorce (before any lifestyle changes are made and loans taken out, for example). The latter still seems preferable to me, especially given today's moral norms regarding marriage. Both involve broken promises and heartache, I'd think that most red-blooded American astronauts would be less inclined to want to experience that in a very public setting. Is it better to be looked at with suspicion and possibly moral opprobrium or to be a figure of pity? I hate to be pitied.