signs of flirtation? interested or not?

Okay, so I'm quite confused and I thought since I'm a girl a boy's perspective would help more. Here we go. I was on this camp with lots of exchange students and we spent 3 days there. I already knew them before hand. One of them actually a guy kept staring at me for like the first two days... So at the party on the last day I thought hey he's quite cute so why not hook up with him. Except when I tried to get his attention, I asked "why have you been staring so much at me lately", and he was like "what can't I" in which i answered "yes" buuuuut then he didnt seem interested in me at all. It was just weird cause why would he otherwise stare that much... But then he started telling me how i was such a beautiful woman in an apologetic way, then he tells me that he might have something going on with a girl at his school so he didnt wanna ruin that. And I was like "okay i understand" but then he says that one kiss is fine. Wtf? so we did... but what i dont get is he was trying to hold back with me yet afterwards he starts hooking up with every girl at the party.... this is just really confusing.... is it cause he's simply not interested? or he's a player or something??? thank you so much for reading (: