About a girl who loved him, and was ready for commitment, but he wasn't. The first half, her perspective, seems to be all metaphor - a broken relationship that she can't forget - he's the stray dog.
The second half is more literal - his perspective at the time that he knew her. He ultimately realizes that what he wanted to go off and search for is really what he had with her... but its too late to mend broken hearts.
About a girl who loved him, and was ready for commitment, but he wasn't. The first half, her perspective, seems to be all metaphor - a broken relationship that she can't forget - he's the stray dog. The second half is more literal - his perspective at the time that he knew her. He ultimately realizes that what he wanted to go off and search for is really what he had with her... but its too late to mend broken hearts.