So, I've known this friend for many years like 8 years and what I've noticed was that he's never, ever mentioned a girl. When I ask him if he likes anyone, he doesn't answer and changes the subject. He's never expressed any interest in girls, not even saying that one is hot. He also, whenever I say something about guys, he says, "I"M not gay!" and gets all mad. I think he's gay, should I ask him?