In the boardroom, the rule is simple: if a venture isn’t yielding returns, you cut your losses. You pivot. You reallocate capital to where growth is possible. Yet in matters of the heart, even the most rational, high-performing individuals abandon these principles. We’ve been conditioned to believe that persistence proves love—that effort can convert indifference into affection. But in adult relationships, there is a harder and far more useful truth:  if she doesn’t love you, neither should you. This is not cynicism. It is discipline. Withholding emotional investment from someone who cannot reciprocate is not rejection—it is alignment. It is how you protect your time, your energy, and your sense of self. The first principle to understand is the sunk cost fallacy. In business, it’s recognized as a cognitive bias—continuing an investment because of what has already been spent, rather than what future returns justify. In relationships, it shows up as staying because of time inve...