I’m lucky to count the brilliant couples therapist Esther Perel as a mentor. She once explained to me the difference between a love story and a life story. There are many people with whom you can share a tryst but far fewer with whom you can build a life. When you’re thinking about who to marry, she says, don’t ask yourself: What would a love story with this person look like? Instead, ask: Can I make a life with this person? That’s the fundamental distinction.