My boyfriend just told me how much I have to pay to live with him?

It could be that you boyfriend is attempting to make it financially improbable for you to live with him because he really doesn't want you there and is afraid to come right out and tell you. By making your part of the rent as much as he has he is probably aware it is more than you can afford. Maybe this isn't a good time for you to move in with him, but he is reluctant to come right out and tell you how he feels. Regardless, if you can't afford this much there is no sense dwelling on the concept. You will need to stay where you are until he either lowers the amount you will need to pay or you are in a position to be able to pay more. In the meantime you might need to determine if he really wants you to move in.