Monogamy is absolutely imperative. The minute you start fiddling around outside the idea of monogamy, nothing satisfies anymore. Suppose you make love to an exciting woman other than your wife, it can't remain enough to go bed with her there must be something else, something more than the absolute compulsion of the body. But if there is something more, it will eventually destroy either you or your marriage.

In James Robert Parish The Hollywood Book of Breakups, John Wiley & Sons, 20-Dec-2010, p. 348