The boy i like is taken, and he makes me think that he likes me.. please help!?

i'm 15 years old. A boy that i became friends with this year and got really close to is 16. He has always been there for me about everything i wanted to talk about... and i just noticed that i am really infatuated by him. He just got into a relationship about 3 weeks ago.. and before he was in one, he would always ask me who i like... and he says stuff to me like.. "i wish there were more girls like you" and... whenever i bring up the 18 year old that HE DOESNT LIKE.. because he doesnt think he's any good for me.. Hell say stuff like .. you can do way better then him" and ill reply with a i dont think so and laugh.. and then hell say.. oh thanks for telling me that joe is better then me.. he always compares himself to joe. and he gets mad when i talk about him.. and he always asks me to hangout. i really want to tell him how i feel.. but i'm scared cause.. he's taken. he always makes sure to make it clear that he's hanging out with his girlfriend or that he misses her.. and i think its to get me jealous. what do you think?