Clark couldn't tell you that you were dating. Everything was difficult for you two, to put it mildly. Because of his secret about his abilities, he can't be the most honest or punctual.

But when he sees you with other guys, he just goes crazy. It annoys him so much. Even if this guy is new and you're just showing him around the school. But for Clark, this new guy is too close to you.

Clarke stands by his locker and looks at them. He's even willing to use his heat vision to keep that guy from looking at you.