Does my crush have a crush on me? LGBT?

I'm a boy and I think I'm BI. I prefer girls but I have this Facebook friend who is a boy. He is Drop Dead Gorgeous and super cute. We chat a lot but he already has a Girlfriend. We became close and he keeps on posting on my wall telling me how handsome I am everytime I change my Profile Picture. When we chat, he always asks about my lovelife and also about my sexual orientation if I'm Bi. I just laugh at him everytime he asks. Everytime I help him with his favors, he keeps on telling "MWAH" which overwhelms me alot. Is he being friendly only or what? I know he has his Girlfriend but he keeps on sharing to me that they don't understand each other that much that's why he'sacting a little strange. Please help!