I would guess (and I emphasize guess) that she feels threatened. In your kilt all these women come to you (regardless of whether it is 1 or 50) and give you attention, how can she compete? what you really need to do is first explain to her that Scots, Samurai, and a myriad of other extremely MANLY men wore kilts, and MUGS. But most importantly you need to look her square in the eye and saw something like "You are the only women whose opinions matter, the only one I want attention from." tell her you love her, only her and have no interest in anything else. often change fills people with fear. I am guessing you probably didn't get a lot of women coming up to you with your wife there making comments. this is new, now is wondering if she could lose you to one of them.
in short women feel threatened because most men are lead by our nether regions. just reaffirm your commitment to her, and do it often. She's your wife, don't blow off her feelings, address them and try to put them at ease. But don't be held hostage by them. either.

of course this is my opinion and I could very well be talking out my ****.