Song sung by Garth Brooks at Sunday, December 19, 2010 Nashville Benefit Concert?

Garth Brooks sang a song at this concert that I have never heard before, but I LOVED it! It was about two people that had always been friends, but now are more than friends. I have searched endlessly for anything that might possibly relate to this, but can't find anything about it. Does anyone have a clue what song I'm talking about? It definitely relates to my situation, and I just have to hear it again (it may be the first dance)!