Why is this guy curious about other men talking to me?

He is an intern I’ve talked to a few times. He mentioned he had a girlfriend but i caught him checking me out several times and he seems a bit interested in other men talking to me. For instance when I talk to a male coworker he would take glances, walk past us or just ask me who this guy was and what we were talking about. Is this normal curiosity or indicative of deeper interest? I noticed that he remembers every little detail I tell him but that might just be his personality

He seems interested
Doesn’t mean much/just normal small talk
Select gender and age to cast your vote:
Why is this guy curious about other men talking to me?
Post Opinion