This principle—that your spouse should be capable of becoming your best friend—is a game changer when you address the question of compatibility in a prospective spouse. If you think of marriage largely in terms of erotic love, then compatibility means sexual chemistry and appeal. If you think of marriage largely as a way to move into the kind of social status in life you desire, then compatibility means being part of the desired social class, and perhaps common tastes and aspirations for lifestyle. The problem with these factors is that they are not durable.
