It could be that he is stringing you along. It's hard to not know when someone is attracted to you... perhaps he sees you as a "safe" female to pal around with, and perhaps on some level you see him as a "safe" man, since you know he won't be after you sexually. Often when a straight person is attracted to a gay person it's because the straight has some baggage of their own which leads them to fall in love with impossible people. Does that make sense? Please don't be offended if I've said completely the wrong thing though.

Do tell him that his jokes hurt. Be prepared for the friendship to change though. I'm sorry.