At the question regarding just what the term was, Isaac was nodding his head before looking to Anna and then back to Elsa. Boyfriend was probably the right term, they hadn't talked about it, but they were dating, so that, presumable, meant he was her boyfriend and she was his girlfriend and they just happened to also be roommates. Completely normal.
"She acts like she doesn't cook just about everything we eat that isn't take-away food." And maybe a lot of it was stuff that most people wouldn't have as a dinner -grilled cheese or steak snacks or brownies by the trayful, like he was in any way better at keeping them fed. If it was Isaac's turn he usually just brought something back in from the restaurant.
It wasn't like either of them needed gourmet meals though.