f150k,

You have received quite a few responses. Some tongue in cheek, some sincere and some bordering on rude and intrusive.

But I was talking to my wife about this. She is a very smart women. Her comment to me was that from a woman's standpoint it may not be that she does not like you in a kilt.
It may be that she is feeling protective and does not want others to think bad of you. She may be afraid of what others may say or think so gives you the impression that it is her disapproving.

As some others have said. If it is possible, find a place where there are others in kilts. Once she sees that you are not the only one she may relax the "protect him from harm" attitude.

But in the end this really is something you need to talk to her about. I'm afraid that an on-line forum will just make matters worse. Forums don't make good "Dear Abby's" as you can see from some of the replies.