Can I reverse a relationship that was based off of sex between a cancer man and a libra woman?

I'm a libra and i like this cancer. He is a wonderful guy and at first he was just someone that made me laugh. And i liked that about him but i never thought it would escalate into anything but friends. That changed on prom weekend when we had sex. After that we started hanging out and i started to really like him and i want more but i believe that it's just a physical thing for him. So my question is how can i change that mind set and let him know that i want more. So to all the cancer males and females will you help me try to turn this thing around and try to make our sexual relationship be just a relationship because i really wanna be with him because he's a great guy who is real