Does anyone know of any songs about liking someone who already has a girlfriend/boyfriend?

If so, list please!

Don't Cha by The Pussycat Dolls
Girlfriend by Avril Lavigne
Teardrops on My Guitar by Taylor Swift
It Sucks by Skye Sweetnam

That's all I can think of off the top of my head.

Eric Clapton had a hit with "Layla" twice. It's about how he wanted to schtup George Harrison's wife. Eventually he did, and she left Harrison for him. Somehow, they remained friends.

Jesse's Girl

Rascal Flatts - Winner At A Losing Game

maybe....

"Tear Drops on my Guitar" by Taylor Swift