As long as marriage has existed, so has the affair. In our collective imagination, the mistress is often painted in extremes—either a romanticized heroine or a demonic homewrecker. We think of figures like Madame de Pompadour, whose influence over Louis XV arguably plunged France into the disastrous Seven Years' War, or Monica Lewinsky, whose affair with Bill Clinton triggered a national political crisis in the most powerful country on earth.

These stories create an archetype of an insidious, cunning woman who masterfully subdues powerful men. We picture a brilliant manipulator in a pink bathrobe. But this image is both overly romanticized and unfairly demonized. The truth is often far more mundane. From the perspective of family psychology, the appearance of a mistress is not the cause of a marriage's collapse but rather a consequence of its existing fractures. In a strange and painful irony, she can become an external, stabilizing element for a relationship in crisis.

The Support for a Tilting House

It may sound contradictory, but let me explain how it works. When dissatisfaction takes root in a marriage—a lack of gratitude, admiration, sex, emotional support, or shared interests—it first creates tension, then open conflict. When a man feels a persistent need is not being met by his wife, he may seek to have it satisfied elsewhere.

Once he finds a mistress who provides that missing piece—be it emotional empathy, attention, or physical intimacy—the pressure within the marriage often subsides. He stops demanding it from his wife because the need is being met elsewhere. The tension eases, the conflicts fade, and the marriage appears to improve on the surface.

Think of your relationship as a house. A strong, stable house needs no external supports. But if the foundation begins to sag in one area—whether due to a lack of emotional empathy or a failing sexual life—the entire structure starts to tilt. At that moment, a "support beam" in the form of a mistress might appear to prop it up. A mistress is never the cause of the end of a relationship; she is always a symptom of an unsatisfactory one. And it's a mistake to reduce this to just sex. If sex were the only need, it would be far simpler to pay for it. The role of a mistress is often far more complex, servicing a hidden emotional deficit within the family structure.

It's crucial to distinguish this dynamic from pathological infidelity. I recall a former colleague, let's call him David, whose job involved frequent travel. Everyone knew he had flings in every city he visited. At a corporate party once, he drunkenly raised a toast: "To the affair! A good one strengthens the marriage." We all politely clinked glasses, likely thinking his own marriage must be built like a fortress. But that behavior—a compulsive inability to remain faithful—is a different issue. We are talking about a long-term, stable relationship on the side, one that serves a specific, stabilizing function.

The Crossroads: Three Strategies for a Wife

Discovering your husband has a mistress is a deeply painful blow. The initial reaction isn't thought; it's a storm of emotion. "He's a traitor," "How could he?"—these feelings of anger and betrayal are completely valid. It’s essential to process these emotions, but confronting your partner in the heat of the moment will likely only worsen the situation. It is better to approach him once you have a clear strategy.

When a wife learns of an affair, she stands at a crossroads with three potential paths:

1. End the relationship immediately. This is a valid choice, but it is not always the most constructive one.
2. Accept the new reality. Some choose to do nothing, allowing the relationship to continue with this external "support" in place. Many marriages exist this way for years.
3. Stay in the relationship and work to remove the support. This path involves deciding to fight for the marriage by making the mistress redundant.

How to Make the Support Obsolete

Let's assume you choose the third path. Now that we understand the mistress is performing a stabilizing function, you must realize that simply kicking her out is like yanking a support beam from a leaning house. The structure will only tilt further and eventually collapse. Radical action is not the answer.

Instead, you must figure out what function she is performing. You don’t need to hire a private investigator. You simply need to reflect. What were you and your husband arguing about before things suddenly went quiet? He kept bringing up a need, an expectation you couldn't or wouldn't meet, and then, one day, the arguments stopped. It seemed he just "got over it."

He didn't get over it. He just got it somewhere else.

That "something" is the function the mistress is serving. The logic, then, is simple: you must start providing that need within the marriage. When you do, the house begins to straighten. A support beam is no longer needed for a house that stands upright on its own. She will likely fall away on her own, without you having to wage a direct war. From my professional experience, a wife can almost always identify the core reason for the affair, and if she truly wants to, she has the power to satisfy that need herself.

Why the Wife Holds the Winning Hand

When a mistress comes to a psychologist asking how to get her lover to leave his family, it's a formidable challenge. When a wife asks how to get rid of a mistress, the task is far more straightforward. The wife is always in the more advantageous position. Here's why:

• Inertia. A body at rest tends to stay at rest. Leaving a family is a monumental upheaval. It is far easier for a man to maintain the status quo, telling his mistress, "Let's just leave things as they are for now."
• Social Integration. The husband and wife share a world: friends, relatives, colleagues, and a collective history. This social fabric is a powerful anchor.
• Children. While children don't guarantee a marriage will survive, they are a powerful factor that weighs heavily in any decision to leave.
• Finances. Divorce is, for most men, a financially devastating event. This practical reality is a major deterrent.
• The Primary Relationship. Most importantly, the mistress is a support, not the house itself. Even in a troubled marriage, the wife still satisfies the majority of her husband's needs. The mistress is only filling a gap.

If a wife chooses to enter this fight, the odds are overwhelmingly in her favor. Understanding the dynamics at play is the first step. By seeing the mistress not as a villain but as a symptom of a deeper problem, a wife can move from a position of passive victimhood to becoming an active agent in reclaiming her marriage.

Further Reading

• Perel, E. (2017). The State of Affairs: Rethinking Infidelity. Harper.

  This book explores the complex reasons behind affairs, suggesting they often arise from a longing for a new sense of self or to fill an emotional void rather than simple dissatisfaction. This aligns with the article's idea that a mistress serves a specific function beyond the physical. (See Chapter 4, "The Meanings of Affairs: What Are We Really Looking For?").

• Napier, A. Y., & Whitaker, C. A. (1978). The Family Crucible. Harper & Row.

  Through compelling case studies, this classic text illustrates key concepts of family systems theory. It explains how a third person can be unconsciously drawn into a marriage to stabilize a conflicted relationship, a process known as "triangulation," which directly supports the central metaphor of the mistress as a "support for a tilting house."

• Gottman, J. M., & Silver, N. (1999). The Seven Principles for Making Marriage Work. Harmony Books.

  This work outlines the foundational elements of a strong marital "house," such as building love maps and turning toward each other instead of away. It provides a useful framework for identifying which of these supportive elements may have eroded, creating the "sagging foundation" that might lead a partner to seek fulfillment elsewhere.