Regretting the Sunk Cost

When faced with the fallout of infidelity, it’s natural to feel a deep sense of regret over everything you’ve invested in the relationship—the time, effort, love, and dreams you built together. You may find yourself asking, “Was it all for nothing?” or even feeling tempted to stay in the relationship simply because of how much you’ve already poured into it. This is what’s known as the sunk cost fallacy, and it’s important to recognize it for what it is: a trap that keeps you tethered to something that no longer serves you.

What Is the Sunk Cost Fallacy?

The sunk cost fallacy occurs when we continue investing time, energy, or resources into something simply because we’ve already invested so much in the past—even when it’s clear that continuing will only lead to more loss or pain. In relationships, this can look like staying with a partner who has betrayed your trust, not because you believe the relationship can truly be repaired, but because you feel like leaving would mean “wasting” everything you’ve already put into it.

But here’s the truth: those past investments are gone. The time you spent building memories, the effort you put into making things work, and the love you gave—all of it is part of your history now. Holding onto a relationship out of fear of “losing” those investments doesn’t restore them; it only prolongs your suffering.

It’s Okay to Regret

Regret is a natural part of healing. It’s human to mourn what could have been and to feel sadness for the time and energy spent on someone who didn’t value your trust. Allow yourself to feel that regret—it’s valid and real. But don’t let it dictate your future decisions.

Remember: regret over the sunk cost doesn’t mean you’re obligated to keep investing. Just because you’ve spent years in a relationship doesn’t mean you owe it more years. Just because you’ve given your heart doesn’t mean you have to keep giving when it’s no longer safe or fulfilling.

Moving Forward

Breaking free from the sunk cost fallacy means shifting your focus from what’s already lost to what can still be gained. Instead of asking yourself, “How much have I already invested?” ask yourself, “What kind of future do I want?” Staying in a relationship out of obligation to past investments will only keep you stuck in a cycle of pain. Leaving—or choosing not to rebuild—opens up space for growth, healing, and new possibilities.

Think of it this way: if you were holding onto a stock that kept losing value just because you’d already spent money on it, would that make sense? Or would it be wiser to cut your losses and invest in something with real potential? Relationships work much the same way—what matters isn’t how much you’ve already given but whether continuing will bring happiness and fulfillment.

A Final Thought

It’s okay to grieve what was lost and regret what was wasted—that’s part of being human. But don’t let regret over past investments keep you tied to something that no longer aligns with your values or well-being. The sunk cost fallacy is just that—a fallacy. It makes no logical sense to keep investing in something harmful or broken simply because you’ve already invested before.

Your future is worth more than clinging to the past. Let go of what no longer serves you, and invest your time and energy into rebuilding yourself, creating new opportunities, and finding relationships that honor your worth.