Why does my crush only chase me if he thinks I'm interested in another guy?

[Tim]

It's kinda like an alpha male kinda thing but at the same time it's not. He will only go after you when he thinks your taken because a) he wants you to be with him cuz he thinks the guy isn't good enough for you or b) he finds it easier to flirt with you when he thinks you are taken. It's hard to explain.
Just tell him how you feel. If he was a real man, he'd tell you how he feels.