Lyric discussion by ike 

Cover art for Empty Chairs lyrics by Don McLean

I'm pretty sure it's about an unexpected breakup. He seems to be naive to the fact that she was giving him all the signs but, ultimately, he didn't know what he had till it was gone!

FYI - Ever heard that song "Killing Me Softly With His Song"? Yeah. The "song" that is spoken of, it's this one! Empty Chairs! And the "his" is Don McLean's!