I saw the very last line as re-defining the entire poem. He talks about how he was fooled, that she was not worthy of his love and how he is over her...carrying those of us who have been hurt along with him...and then he hopes that she loved him too 'sometimes'.

On another theme; I wonder whether there is a world, somewhere in this universe, where more poems are written about the joys and happiness of being loved, than of the pain.

I seriously doubt it