What are some good song lyrics that describe an apology?

There's a guy I've been friends with for 6 years. & he's always did he loves me & I always turn him down. I do have feelings for him, but recently I waned to grow in my Christian faith so I avoided any romantici relationship at all. Anyway, this guy has a new girl. & its kind of like a "you don't know what you got till its gone" situation. He loves music & I want to find the perfect song to describe how I'm feeling to him.