not easy but...

I'm not an easy person to have sex with. It takes a lot for me to open up to someone that much. But in the past week I've made some different choices.. I've had sex with a guy I've known for 3 weeks twice and we aren't even dating yet.. I'm ashamed that I've allowed myself to do this. I don't want to be used so what do you guys recommend I do in order to assure he's not just using me for sex? I really like him and I think he really likes me. I'm just scared of being played.