What is he trying to tell me?

this boy i like was talkin to me on msn and suddenly starts goin on bout this reli fit girl on his contact list called mary. i was just like 'ooo get in' as a joke but i do admit i felt quite jealous. this guys older than me and has lots of girls after him but does flirt with me subtly and i do it back. wat was he tryin to do with mary? get me jealous? or ask advice as a mate?