The guy I'm dating always jokes I should be dating his best friend?

[Subhumangirl]

Me and this guy have been getting super close over the past month of dating and it is moving in a great direction eg. planning to meet each others parents and meeting each others friends. One little problem is every now and then he will find something out about me and exclaim that I should be dating his friend. I had this happen once before and it turned out he didn't want anything more from me than sex. Is it just another way of saying "you and my friend will get along when you meet" or is he really trying to push me away and really doesn't mind the idea of me with his best friend. I tried to trigger something by asking if he's hot and he said he is. I just want to nip this in the bud but we have been having a lot of heavy conversations lately. What should I do?