 My name is Saad Akhnin, and I'm the author of Malignance of Love, Narcissism Revisited. The tendency to remain in bad relationships, the tendency to stick to partners who are abusing in hopeless, sexless, loveless, doomed marriages and other unions. This tendency is known as the sunk-cost bias, or sunk-cost fallacy, or the concord fallacy. Co-owning a business or property, shared memories, and especially co-parenting, tend to cement this bias and pile it on top of traumatic bonding and fused relationships. What is the sunk-cost fallacy, or bias? Well, in day-to-day life, we tend to throw good money after bed, just because we are already invested in a project, or in a stock. We watch an atrocious movie to its end, because we have already spent an hour doing exactly the same. We eat food that we have ordered, even if it sucks. We keep clothes that we never wear, simply because we have paid for them. It is a particularly pernicious brand of loss aversion, the proclivity to avoid waste. This utterly irrational behavior is motivated by malignant optimism, an overestimation of the probabilities of positive outcomes if we just keep going or keep doing something differently. Someone said that the definition of insanity is doing the same thing, expecting different outcomes, and that's a pretty good definition of the sunk-cost bias. We are also afraid to look foolish if we admit to having made the wrong decisions consistently, and this is a form of narcissistic injury. We sometimes feel responsible and guilty for having made these decisions in the first place, so we atone for our mistakes. Of course, the rational thing to do is to cut your losses and abandon the dysfunction of relationship, but divorce statistics aside, surprisingly few people do so in time. And what are the results? What are the outcomes of this reluctance? Wrecked marriages, hateful exes, bruised children, and crumbling enterprises. The sunk-cost fallacy or bias ends up sinking the people who perpetrate it.