Is he trying to play me? Does he like me still?

This guy and i were this close to dating, and we kept talking everyday, and i mean EVERYDAY. we would flirt, laugh all the time...and then tonight i found that he just started dating this girl. Did i mention i found it on facebook? so then i contact him saying that i didn't know he was dating someone, and he justifies that it's not really serious, and he still wants us to be friends even if we date other people. but we were almost a couple! i am a bit upset, and really hurt. what should i do?