Perhaps love is a minor madness. And as with madness, it's unendurable alone. The one person who can relieve us is of course the sole person we cannot go to: the one we love. So instead we seek out allies, even among strangers and wives, fellow patients who, if they can't touch the edge of our particular sorrow, have felt something that cuts nearly as deep.
Through all this ordeal his root horror had been isolation, and there are no words to express the abyss between isolation and having one ally. It may be conceded to the mathematicians that four is twice two. But two is not twice one; two is two thousand times one. That is why, in spite of a hundred disadvantages, the world will always return to monogamy.