It's folly that women measure their happiness with the pleasures of the bed, but they do. And when the pleasure cools or their man goes missing, all they once lived for turns dark and hateful.
Sometimes I know what my characters are moving away from or toward; more often I just wait and see. For instance, though I knew Sinkler in 'The Trusty' was going for water, I did not know that he would meet a fetching young farm wife until I got him into her front yard.