I was thinking about what this song could mean. And I thought, one way it could be interpreted is a man leaving his girlfriend to go to war. A soldier. I thought of all the ways it relates to this idea. Such as, when it says 'i know you can't come back home til they're singin' As in, til the officers or whatever say it's time for the troupes to return. It's a good concept, but not the only one.