Having just beaten the game for the first time in a few years, there is something odd about the end. Mind you, I find Melodies of Life to be a beautiful and wonderful song, but thinking on it it's bizarre that's the song they use at the end of the game. BoB, you may want to stop reading here for purposes of your current play through.
Anyway, Melodies of Life is a song whose lyrical content doesn't really match up with the reunion of Garnet and Zidane. The song is clearly a woman singing about a cherished, yet lost, love. It's about looking back through her memories and remembering the man she loved, and may still love, fondly, even if they are not together now. Why they aren't isn't really important.
This does not quite match up with Zidane and Garnet. Am I off here?