Am I being used?

I've been really good friends with this guy and he's 13 years older than me. I would love to date him and be in a relationship with him but I think the age gap gets to him. We recently started having sex but it's only when he wants it. He doesn't kiss me any other times then when we are going to have sex. He's always talked about how he only has sex with people that he truly cares about. So does it mean he truly cares about me or is he just using me? What should I do?