Does my crush(who still has gf) likes me or just playing around?

I had this huge crush over this guy who is a customer in our cafe and is staying in the dormitory upstairs in our internet cafe. He was really nice and charming that i liked him but then i learned he already has a girlfriend. I didn't want to be second best nor called a boyfriend stealer so i tried not to be so close to him.But suddenly after a few weeks. He suddenly changed like talking to me anytime he gets a chance to.But he never asked my number.In the hall he smiles and says hi a lot, he even make comments that his day is complete because he saw me...(so flattering but i really really doubt it!) He even said i miss you once when i ped by him... But in jokingly way i know.. I tried not to fall for him coz i know i would end up hurt since he already has a girlfriend and i don't want him to dump her for me if ever he thinks about that...i don't want somebody to get hurt because of me..But why is he acting that way now? i had a feeling there's a connection with what happened recently when his friend,someone new i just met a week ago, asked for my number and showed some unwantic romantic interests, i refused to give in and not gave my number...And since then , my crush is acting so sweet and charming to me...why would he be doing that just bec. i don't want to return the feelings his friend have for me bec. i just met him and that he's not my type. What should i do so that my crush would give me a respect that a lady deserves bec. i am starting to felt being played around...Please help me what should i do?