Light Year by Gregory Alan Isakov
To me this song is about loving someone, like really really loving someone to the fullest only for you to fall out of touch over time. Its about looking back and remembering, asking yourself what you did wrong and what you should have done differently. Wondering if maybe you made a mistake and if it weren't for you you would still be in their life. But in reality it wasn't any ones fault, people just fall out of synch sometimes, and its ok to feel sad about it.