Defense Mechanism?

Sooooooo I met this boy and he pretty cool. We talk often enough and I think we know enough about each other to form certain generalizations about each other's personalities. He believes that my "game" is a defense mechanism. I don't let boys get close. Which I've heard before, I just never thought it was so easily detectable. Whoops? I thought if this was a good or bad thing, if my offensive defense was actually harming me. I think in some ways it has but I also feel like it's very necessary. People, especially boys can be, cruel. I don't mean to sound sententious but why should I let anyone get close when 90% I end up hurt?