Okay, so I just discovered this song not too long ago, and it's kind of scaring me how perfect it is for one of my stories. Clarity by Jacquie Lee (I don't like the original version, sang by Zedd, so I'm going with Jacquie's Voice performance).
Their love was a tragedy - but it allowed them both to see clearly for the first time in their lives. Even in the darkness, they found clarity.
Hot dive into frozen waves
Where the past comes back to life
Fight fear for the selfish pain
It was worth it every time
Hold still right before we crash
Because we both know how this ends
She's forced to relive the past; he refuses to let it lie. She teaches him how to live for the moment, and he shows her that she is not responsible for what happened so long ago.
Yes, they both know how it will end. But they let themselves love anyway.
(The first video is the full version; the second is her singing it live on the Voice. It's a shorter version, but it's worth it to see her sing it.)