I think it's an interesting question because one might wonder if there's a subtext of, office personnel and anyone else coming from an office, wear business attire because no one has time to change, but other folks without those limitations can dress for a party! So it would not make sense for them to aim for a required dress code of "cocktail" or even "festive attire".
So on the one hand, I would not wear jeans if you have a nice "business" alternative so that, as per Emily, you and your husband blend in to the office group.
Of course that won't prevent the business ladies from trying out the "day to evening" change of top, jewelry and shoes to look less business-like! But ideally it would mean dress and cardi or blazer, skirt and same, "suit" trousers and jacket, that sort of thing. And if the jeans are quite form-fitting, that also would be farther away than say crisp trouser-style jean.
It really boils down to whether you want to follow the dress code as stated and if so, the practicalities of whether you have an outfit at your disposal that comes closer to the dress code than the jeans look and yet is flattering.
The next level is if you wear the jeans, do you do "sparkly top" because, hey, I was at home and it's a party!...or do you have a more formal blouse or top look with the jacket. Of course, the universe won't explode if you wear dark denim, and there may be other wives that show up in any number of other "dress code" outfits--(I say wives because, IMO, male spouses are likely to have at least one suit or slacks/sportcoat and be happy to wear the simplest thing!)
I think at some level it will depend on how the total outfit looks--grown up, tasteful, mixes well with office-dressed people.
