Problem with roommate. Help!?

There's really no other way around the fact that you will have to confront him. As hard as that may be for you, it's the only way to get the situation under control. Once you get to talking you two have to evaluate and analyze your living and financial situations. And speak you mind and tell him exactly what you're telling us. Also it wouldn't hurt to write out a budget on paper. It would be good to have a physical representation of what needs to happen in terms of splitting costs for your living arrangements etc...