You carry emergency gear primarily to help others in need. What if one of your wife's friends was thinking of doing something, perhaps something your wife would advise against, where certain supplies could drastically reduce the potential negative consequences? What if it were one of your adult children?

Need an excuse? I should say not. Rather you should, with maximum subtlety and indirection, allow your wife to wonder why she does not carry such things as a concerned and prepared friend and parent.

Some insights gleaned from attending my nephew's recent wedding (he was the ringbearer at mine and DW's wedding).

what I brought:
knife: EDC - wasn't used but still good idea to bring it (note: there was a small swisstech pliers attached that were not used)
light: EDC - not used but again good idea to bring
mints: the mini tin is my EDC, added a bigger tin as well - not used until the reception when we finished eating
hankerchief: added, had 4 on me (not used); DS had 2 on him until he handed one to teary-eyed DW (note I normally EDC a garbage bag wrapped with a bandanna - I opted to eliminate this in favor of the extra hankys)
pocket tissues: added, mine not used but DW had some that were used
note: there were tears, but the wedding was held in the same building/room as the reception so we were already sitting at tables. Also, if you ADD items, you have to remember you have them with you before you think to give them to somebody.
billfold: EDC, dollars for the dollar dances
lip balm: EDC, not used
keys: EDC, not used other than for the car
Flat bottle of tums: EDC, not used until after I ate (personal issues, not bad food)
Appetite: EDC, definitely was used
great thirst: EDC, was used but only for non-alcoholic beverages


what I didn't bring:
flask: no alcohol at the wedding except a few bottles for the wedding party/toast (figured it would be in bad taste if I tried bringing my own)
condoms: I would definitely not be trying to explain those to DW (though others have mentioned good reasons for including them - and if you're single why not)
mini-kit: wouldn't have been used anyway
FAK: luckily we didn't need it
sewing kit: again we luckily did not need it
lighter (or other firestarter): didn't need it
gun: didn't need it

I'll be adding/subtracting (for the next wedding):
Add FAK: a small fak with OTC pain meds and bandaids or moleskin - for blisters from dancing at the reception and any other boo boos
Add small flat sewing kit: a great idea, especially if it includes (or add) safety pins
Minus Large mint tin: stick with just the small one
minus large SAK knife: take smaller SAK instead (yet another knife purchase, DW will kill me)

One more important consideration. Like ireckon said keep it minimal, especially if you are actually in the wedding.

Tell her that you want to relive what happened when you first met?

You have got to carry your EDC. Because a) your S.O. know's that you have it and b) when some thing goes pear shaped your S.O is going to stand there giving you that "Well....?" look.

Mind you: She is also going to exercise her bragging rights about why she married / is going to marry you.......

If your the best man, then a good speech is a prerequisite;

http://www.youtube.com/watch?v=lXpmHuCE9Ls

1 wedding down
Items used - pen, safety pin, spare shirt

Items forgotten: sharpie, sunscreen(!)

Ah, a case for matching equipment to environment?