Dating guy soon after he broke up with his girlfriend?

[Glasses Chick]

A group of us went out to bars the other night, there was one guy I didn't know. When he got into the car, my friend asked him if he was in a relationship. He said that they had broken up two weeks ago. (From what I can tell through Facebook and talking to our mutual friend, the relationship was only for two months.)

The next day he asked me out. We went out and it was great, but how can I tell if he's dating me for me, or just to have another girl by his side? Are there any signs I can watch out for?

He's the first guy I've really been interested in in over a year, so I don't want to get overly-invested in something that is temporary.