Room mate moved into the bigger room?

My boyfriend and I decided (maybe badly) we would move in with his friend. We were living 2 hours away at the time and decided to go to the same school where this room mate (guy) lives. We helped find the place over the phone and when everything was said and done and verbal agreement was made with the landlord and he signed the lease since he was on site. The landlord said it wouldn't matter who signed the lease. The verbal agreement had been made and she had our names and our car license plates (for parking). My boyfriend and I would move up two months later. We were under the impression that we'd get the bigger room since there are two of us, but to our surprise the guy moved into the master bedroom and left us with the room half the size. Our closet is meant for one person and we're really cramped in our room and getting quite sick of it. Additionally, the guy acts like he runs the place...turning the air off when we turn it on without consulting us (our room is hot), getting flustered when we're using our TV in the living room (it's attached to the DVR which is under our name) and we pretty much do all the cleaning and buy things such as toilet paper which we find he takes and stashes sometimes. He even asks us to leave when his girlfriend comes over while we go out when we want alone time or wait for him to be out of town. He claims they're more serious than us so that's why (they've been dating two months longer). We make him pay a little extra but I'm getting irritated more and more with the lack of space and the overall attitude. Any suggestions? The place is cheap so we don't really want to move out.