It is uncommon, but does happen. I know of one couple in that situation and honestly it wasn't a big deal. He was good dude and hung out at parties, going out to bars, etc. No, he didn't go to any spouses stuff...but that'd be super gay if he did. Also if you're talking kids in the future, you want to figure that out sooner rather than later. He may not be OK with being stay-at-home dad while you go fly jets. He can find work just like any other spouse. It may not be a typical arrangement, but it's certainly not impossible.

what's it like for civilian husbands/ boyfriends?

Of the female pilots I've known, only one was married to a non-military guy. Ditto Brabus - not a big deal, he came and hung out at the parties and squadron events, but didn't do any of the spouse stuff.