‘The Shadow Prince’
Perhaps the reason that unrequited love hits us hard is not just because of the person that we cannot have, but because of the life we cannot have. The unattainable, lost person may be more important to us for the ‘could have been’ life that they represent than for who they actually are. The object of our love or adoration (I think they may be different things, though I’m hardly an expert) is also a reflection of who we would like to be and how we would like to live.
In a way, unrequited love makes us characters in a ghost story where we are haunted by out own lost possibilities.