My guy is not in a fraternity. His university has about two inter/national fraternities, and one of them keeps giving him bids but he turns them down every time. I'm starting to get a kick out of it! He likes the guys, but he doesn't really see the point of joining a fraternity.
He's cool with me being a DZ, though--he didn't have a very good image of sororities because of the ones where he goes to school, but hopefully I've changed that a little.