My wife didn't want me going out in a kilt either (at first). She thought I'd get heckeled and she hated seeing me get "hurt". I think she felt I'd be made fun of.

I wear a kilt most of the time that I am not at work. As long as I wear underwear (when she is around) she is okay with it. Now when we go out she knows I'll get a few "nice skirt" comments but she is comfortable knowing I don't care what anyone thinks. She also used to worry I'd get into a fist fight over my manliness. (how do you spell that one?) But she she realizes that it is not a big deal.

Now she is mostly worried that I look "too cute" and some other chickies will try and snap me up.

My advice...wear it at home first. Get comfortable with it (get her comfortable with it)...Then short trips to places were idiot men don't hang out (grocery stores). Whenever you are in public with her, shower HER with attention. Show everyone you don't care about what they think (about your cloths) but show her that you love her and that you are mature enough (man enough) to shrug off a few dumb comments. Don't counter attack ignorant people or their comments. She'll end up thinking you're pretty cool...
and if she doesn't...well at least you'll be wearing a kilt!