the sunk cost fallacy

It's awfully hard to believe that there's no use in crying over spilt milk. All our instincts tug the other way. The more time, money, blood, sweat, or tears you've invested in something, the harder it is to walk away. When you've ordered a heaping bowl of double chocolate mint swirl, even if, after eating half, you find you're stuffed, if you don't finish the whole thing, you'll have wasted your money. When you've spent a decade in in a relationship that has now gone sour, if you split up, those years of devotion will become meaningless. When a country has lost thousands of its soldiers in what turns out to be a futile war, withdrawal would mean all those lives were sacrificed in vain.

Of course, this line of reasoning is completely irrational. What you've already invested, what economists call your "sunk costs," are irrelevant when you're trying to decide what to do next. The money, the years, the lives are already gone. You can't get them back no matter what you decide to do. You should ignore the sunk costs and weigh only present and future costs and benefits. Cut your losses. Don't throw good money after bad. Let the dead bury the dead.

But it's not easy to put this particular theory into practice. Because I've put so much time, money, and effort into the idea of having a baby, because of the losses I've suffered, it's become harder and harder to draw a line and say: this is it. The temptation is to keep going and going, not just because I want a happy ending, but also because I hate the idea that all I've done, all that's happened is pointless. While I certainly don't have to make any final decisions yet, looking ahead, I can see that as the financial and emotional costs mount, it's going to become harder to decide to stop, harder not to keep going forward no matter what. It's a vicious cycle. The more I invest, the easier it becomes to invest more. Sometimes it's not only the costs that are sunk.