Songs about a guy who's falling for you but you feel nothing for him because you're in love with someone else?

I need songs idea for a musical in my school. What's on my mind is
something like Taylor Swift's "The Way I Loved You" which is about an
ex, but anyway, it's the same situation. The guy who fell for you is
perfect but you can't get over the other guy, something like that. Any
idea?

Thanks!