Why would a crush (of mine) talk to someone else but still get nervous around me and act secretly interested?

My crush talks to another girl but acts nervous and fluttery around me.

He sometimes acts like he wants to talk to me , glances at me when I’m not looking, and mimics my body language (getting up the minute I get up in class). I have a feeling he is talking to someone else but I’m not sure as of yet. If he is, what would his body language really saying about him. How do I control my hopes of a relationship with him?

( I’m 19, not 30 )
Why would a crush (of mine) talk to someone else but still get nervous around me and act secretly interested?
Post Opinion