In a marriage, you must promise to regard the soul you see now as the most important, holy thing. Because time is an unstoppable force. And it will do whatever it can to destroy you. And ultimately, it will win. So you sacrifice superficial things, moods of the day, petty preferences in favor of the purest, deepest parts. You accept and forgive each other's wrongdoings. You don't let anything tear you apart, no matter how gruesome.