[Kevin]

You're in college. Plenty of fish in the sea.

If a guy tells you that you're hurting his grades as a pretext for dumping you, this is a subtle way of him telling you that he's not that into you. If he was really into you, c'mon... grades??? In college, we have a lot of time on our hands. If he wanted to make time for you, he could. He doesn't. Take the hint.