Lyric discussion by globetrotttt 

Cover art for Jewel lyrics by Bombay Bicycle Club

The last line of the song owns the meaning. It's a nostalgic look back upon a failed relationship (either the narrator is telling himself of his regrets, or urging that his lost lover should have her own. It does certainly address the fact that in hindsight, it was rare and beautiful. Too, that we tend to overlook the bad when looking back.