Why is he trying to make me jelous?

Me and this lad are really close. We talk all the way through our registration group and really get on. He's always there for me too. The other night he tried tricking me in to calling him fit and he kept sayin how good looking he is (big headed i know). Well anyway we were talking about a school holiday were both going on and he said his gf is going, 1. i didnt know he had a gf and 2. why is he saying this? Later on i said it would be dark while were on the ferry and he said how romantic it would be for him and his gf, why do i care? hes not a horribble person hes really nice and not a player. Thanks for the help :)