Martin Buber proposed in his book “I and Thou” that true relations (in common english it would be the word ‘love’ but I hate to use the word because he defines love as something wholly different, and the english word definately has lost most meaning). … although after Bill Clinton “relations” became a terrible word as well.
Anyway, his theory is that in order to for love to be meaningful it must be exclusive and must involve reciprocity. At first I disagreed, but now I’m thinking he might be right.