Aw, no problem on the ranting.
It is very hard to deal with the way your expectations are very much turned on their head. It's not about being selfish; it's about learning to change what you expect and learning to appreciate new things. And while people with unfamiliar sensitivities may have completely different strengths than others, they do have interesting things that are wonderful all on their own. If not, you wouldn't be trying so hard to help him.
(Or, for that matter, be with him at all!)
Weddings can be torturous. I actually planned my wedding so that the elements that bother me the most were not a part of it. I had professionals doing my music (no out of tune craziness or tapes for me!), the flowers were mostly unscented or very lightly scented, it was a small church with only around 50 visitors and a short sermon, and NO DANCING. lol Since I've actually forced myself through the torture of being in disco clubs all night with some friends, I know I could make myself do it, but why make my wedding an awful memory?
So, as the bride, it seemed to go by so quickly. I was super focused on the words, on the way people looked at me and each other, on my husband's expressions, and so on. As the best man or something else like that, I can see that your boyfriend anticipates being overwhelmed by the ceremony. When I have to sit (or stand) in public for an extended period of time, I have several things I do. One, I tend to meditate. If I'm standing, I'll make it a body meditation, where I will pretend I am "breathing" through different body parts to help relax. If I'm sitting, I'll count to four on my breaths and repeat indefinitely. One, it keeps you from getting drowsy and groggy. Two, it can help keep your mind off of different body distractions. The only drawback to that is you have to practice a lot prior to the event to make it work. Another thing I do is have a fidget of some sort. I have a ring that is a pocket rosary. I twirl it around my finger or (in a pinch) squeeze it against my joints to distract from sudden sensory issues. Sometimes, I'll even use it as a rosary, if I have the foresight to do so. Since men have the advantage of wearing fancy clothes with pockets at weddings, he can slip something of varying sizes in his pocket and potentially put his hand in to fidget whenever he feels the need, and no one else need be the wiser.
As for the dancing, I understand completely. The moving around, the noise, the press of people around you... there are few social situations that turn my triggers worse than a public dance. (Fireworks and bars come to mind.) If he has obligations as part of the wedding party to dance, then that's understandable, but after that, encourage him to sit it out. There's no reason to stress himself that much. If he needs to make his excuses to the restroom and then return to the tables rather than the dance floor, that will help. It wouldn't bring any attention to it, and he would have a chance to escape most of the triggers and relax for a bit before he returns. Another thing he might consider (if he's very sensitive to sound) is some sort of light ear plugs, but if he were to do that, I would strongly encourage him to try them out well before he goes. Ear plugs can change your sense of balance as well as hearing, so it might be better to leave them off if it makes him feel as though he's going to fall.
Whatever plan he makes to help, work with all the coping mechanisms long before he gets there. As he gets to depend on and trust these things, he will gain confidence in his ability to be able to handle them and depend on them when he needs it most.
Everyone here has different ways they cope with different situations, so I'm sure you'll get more (and probably better!) suggestions. If he finds something he really likes, I would love to know!
