weekend girl

It's like clockwork, same time, same day, week after week. Friday night at 12am he'll text me, wants me, has me, then leaves me by 2am ( I jokingly call him Cinderella bc by the stroke of 2 he "has to leave" and isn't heard from again). I'm his weekend girl; the one he loves to be with on the weekend and doesn't talk to the rest of the week. I only exist at his convenience. We've been doing this for 10 months. I've told him how I feel, that I'm not capable of investing my time, my body, my emotions, my care into him without more commitment. How do I get my point across that I'm not capable of doing this much longer unless he commits to this. It hurts . . .