But sometimes these things are unlinked, so that you can feel profound attachment to one person, while you feel romantic love for somebody else. While you feel the sex drive when you look at a magazine, or conjure up an image in your head, the brain is not well-built to be faithful to a lifelong partner. No wonder we have such trouble. You have studied human patterns of attraction and mating worldwide. Around the world, everywhere, people marry.
Marriage is a cultural universal.
This does not mean that partners are necessarily sexually faithful to each other. In many places, marriage is a business. You don't marry for love. But romantic love is becoming more and more popular around the world, and arranged marriages are becoming less popular. We'll see more romantic love, with all its joys and sorrows.