Clive Barker has an interesting take on this from his novel, Imajica:
"It was the pivotal teaching of Pluthero Quexos, the most celebrated dramatist of the Second Dominion, that in any fiction, no matter how ambitious its scope or profound its theme, there was only ever room for three players. Between warring kings, a peacemaker; between adoring spouses, a seducer or a child. Between twins, the spirit of the womb. Between lovers, Death. Greater numbers might drift through the drama, of course—thousands in fact—but they could only ever be phantoms, agents, or, on rare occasions, reflections of the three real and self-willed beings who stood at the center. And even this essential trio would not remain intact; or so he taught. It would steadily diminish as the story unfolded, three becoming two, two becoming one, until the stage was left deserted. Needless to say, this dogma did not go unchallenged. The writers of fables and comedies were particularly vociferous in their scorn, reminding the worthy Quexos that they invariably ended their own tales with a marriage and a feast. He was unrepentant. He dubbed them cheats and told them they were swindling their audiences out of what he called the last great procession, when, after the wedding songs had been sung and the dances danced, the characters took their melancholy way off into darkness, following each other into oblivion. It was a hard philosophy, but he claimed it was both immutable and universal, as true in the Fifth Dominion, called Earth, as it was in the Second. And more significantly, as certain in life as it was in art."