I need some advice on guys and relationships?

there is this guy(taquito) i really like and hes been dating this girl for like 1 yr and im kinda friends with her. he doesnt like this one guy(chimichanga) i used to like before him(chimichanga) and now he(taquito) is helping me get rid of chimichanga by saying that we r dating when were not. and then the other day taquito asked me if he were single if i would go out with him and i said sure and he wanted to know why and i said personality... so do u think he likes me oh and now taquito leaves at the end of lunch from sitting by his girlfriend to come sit by me! help do u think i should back off or go for it or do u think he likes me or not?I need some advice on guys and relationships?
If he is still with his girlfriend and she is kind of your friend then you don't want to be responsible for breaking up with them. If you really like him then you should tell him that nothing can happen as long as he is with his girlfriend and that he'd have to wait at least 2 months after before you'd get together because then it looks like he actually cared about his ex and wasn't just a jerk who got bored.