Dating/trusting a frat boy?

[peacelovegreek]

A month ago, I met this boy in a fraternity that my sorority worked with during Homecoming and we got to know each other. I've heard from my sisters that he liked me. He's always been shy around me. Yesterday, I met up with him at the library and we headed over to his fraternity's house and we went to his room and I initially sat on the sofa instead of his bed where he sat down. Eventually I got up to look around his room and then sat down next to him. We talked for a good 15 minutes. Throughout that, he laid down on his bed and I was still sitting and it felt awkward so I propped my arm and leaned back. Eventually my arm gave out and I laid down next to him. And he put his around me and I turned to face him and he pulled me in closer and eventually we kissed...yeah! But we just kissed, that was it, NOTHING MORE! And of course his brothers thought otherwise when we walked of his room. And I have always put school first, so he is kind of like the first relationship I've had in a while (since high school and I'm a sophomore in college.) He never really officially asked me out or asked me to be his girlfriend so we're technically not dating. His fraternity is having a holiday party at their house but I'm flying home that weekend, so I can't go. Just being me, I'm having these insecurities because looking at the list of who's going, a good chunk are girls from different sororities or GDIs and a good portion are sisters which is good. I guess what I'm trying to say is, people who are greek, how do you deal with trusting someone to be "good" at parties. I mean we're dating and if he does hook up with a girl, it'd technically would be fine since we're not official...I feel really childish asking this but it has been eating up for a bit.