I'm getting married next year. My fiance has already picked out her wedding dress and now is hinting that she is ready to go choose my tux. I think I should be able to pick out my own wedding tux (I'm a grown man and all). I can't even see her wedding gown, so why should she choose what I wear?
You're right. You should be able to pick out your own wedding tux instead of having your bride-to-be tell you what you're going to wear. And your point is well taken about the fact that you can't see what she'll be wearing, so why should she see what you're wearing? Still though, leaving your fiance totally in the dark about your attire might be a bad idea. If she's already assuming that she'll choose your wedding formalwear, she's not going to take too well to not having the slightest idea of what you're going to look like until the wedding.
Tell her that you are going to go look at tuxes and decide what you like. Then you'll take a trip along with her and ask her she what she thinks. Explain that as long as she lets you make the ultimate decision -- so that you're comfortable and happy with what you're wearing -- you're totally willing to hear her opinion on your choice or the styles you're choosing between. Assure her that you want to look as great as she will, and you're not going to decide on something she'll hate. She might be a little freaked out at first, but hopefully she will agree to it (and be impressed by your initiative). Then you'll get to wear what you want while she gets to feel like she okayed it.
