Welcome, Luna. my compliments on your good taste in husbands.
I can't speak for Scottish, but being Irish is such a blessing that, like being Jewish, you needn't be born that way; you can convert.
I'd echo one of the above sentiments; take a serious look at the "district" tartans. Of what country are you citizens? Or there may be a corporation or organization tartan that applies. But most of all; let him pick whichever one he likes, would look good in, and no one else's opinion matters a whit.