When Trust Breaks: Understanding Infidelity in Relationships

Discovering a partner’s infidelity can feel like a wrecking ball shattering the foundation of your relationship. The pain, betrayal, and loss of trust can leave you questioning everything—whether you’re the one who was betrayed or the one who strayed. You might feel like your relationship, or even your life, has hit rock bottom, with no way forward. As a couples therapist, I’ve seen countless individuals walk into my office carrying this weight, their faces heavy with despair, convinced there’s no hope for repair.

But here’s the truth: there is hope. Not only is recovery possible, but many couples emerge from infidelity with a stronger, more honest relationship than before. In this article, I’ll explore why infidelity happens, drawing on decades of research to help you understand its roots. By unpacking the causes, we can begin to make sense of the pain and see a path toward healing.

The Devastating Impact of Infidelity

Infidelity has been a painful reality in relationships throughout history, its harm so profound that it’s etched into moral codes like the Ten Commandments. Modern research reveals why it cuts so deeply: betrayal often triggers a PTSD-like response, similar to what someone might experience after a traumatic event like a natural disaster or combat. According to Dr. John Gottman, a leading relationship researcher, trust and commitment are the two pillars that hold a relationship together, much like the walls of a house in his “Sound Relationship House” model.

Trust allows you to rely on your partner’s honesty and reliability, while commitment signals a shared promise to stay connected through life’s challenges. Infidelity demolishes the wall of trust, leaving the relationship leaning heavily on commitment alone. This imbalance often forces couples to confront a make-or-break moment: stay and rebuild, or walk away.

For the betrayed partner, this betrayal can fracture their sense of reality. You might experience:

• Self-Doubt: Questioning your perception, wondering how you missed the signs or if you can trust your judgment again.

• Flashbacks: Reliving the moment you discovered the affair, like finding incriminating messages or seeing your partner with someone else.

• Intrusive Thoughts: Obsessing over details of the affair, replaying events, and questioning what was real.

• Anxiety and Depression: Struggling with sleep, mood, or daily functioning as the betrayal shakes your emotional foundation.

• Low Self-Worth: Feeling inadequate, embarrassed, or humiliated, especially if others in your community know about the affair.

These responses are normal, even if they feel overwhelming. Understanding why infidelity hurts so much is the first step toward processing the pain.

The Cascade Leading to Infidelity

If your partner betrayed you, it might feel like the affair came out of nowhere. You may wonder how small relationship issues escalated into such a devastating breach. Research by Dr. John Gottman, Dr. Caryl Rusbult, and Dr. Shirley Glass suggests that affairs rarely happen in a vacuum. Instead, they often stem from a “cascade” of small, seemingly minor moments that erode connection over time.

These moments might include:

• A partner sharing excitement about their day, only to be ignored.

• A dismissive comment or refusal to prioritize time together.

• Unmet emotional needs, like feeling unheard or unappreciated.

Each incident chips away at trust, creating a growing sense of disconnection. Over months or years, this loneliness can push one partner to seek fulfilment elsewhere—whether through emotional intimacy, secrecy, or sexual chemistry with someone outside the relationship, like a friend, colleague, or ex.

This doesn’t mean the betrayed partner is to blame. The betrayer’s choice to step outside the relationship is their own. However, affairs often reveal underlying issues, such as poor communication, unexpressed needs, or a lack of emotional safety. The betrayer may have felt unable to voice their loneliness or hurt, or when they tried, their partner didn’t fully hear them. These gaps in the relationship create fertile ground for infidelity.

Moving Forward with Hope

If you’re reeling from infidelity, whether as the betrayed or the betrayer, know that understanding its causes is a powerful first step. By examining what led to the affair—through the lens of missed connections and unmet needs—you can begin to make sense of what happened. Couples therapy offers a safe space to process this pain, uncover the relationship’s vulnerabilities, and rebuild trust and connection.

In my next blog post, I’ll outline what the recovery process looks like in couples therapy, including the steps, milestones, and commitment required to heal. For now, hold onto this: infidelity is a crisis, but it’s also an opportunity to confront issues, grow individually, and potentially build a stronger relationship than before. You’re not alone, and with the right support, healing is possible.

You can read the next blog post about infidelity here https://www.shaunmcmahon.com/post/infidelity-in-couples-therapy