AAARRGGGHHH!!!!! Sorry, I'm going to have to disagree with all the advice given so far. (Except the bit about efc being a lady!)
I find that if you have the whole 'is this a relationship' conversation with a guy, it makes them run a mile. In your situation I think you're well within your rights to ask if the relationship is exclusive (i.e. if he's planning to sleep with anyone else) but I'd hold off on the whole 'are you my boyfriend bit' - if the relationship is exclusive and he's seeing you as much as he is, I'd let anything else develop naturally - just start making comments along the lines of ' I really enjoy spending time with you' or similar - i.e. gradually getting soppy and he'll soon get the idea!
Let us know what happens!!