What is Infidelity? The Answer to Why Cheating Causes So Much Pain
Author: Dr. Mary Perleoni, Ph.D., LMHC
Updated July 2, 2025
Infidelity can be one of the most devastating experiences that can happen in a relationship. Whether it involves emotional or physical betrayal, the effects can ripple far beyond the immediate fallout. Infidelity challenges trust, creates emotional turmoil, and forces individuals to confront complex questions about their values, boundaries, and commitment.
Whether it surfaces through a one-time affair or a continued emotional connection with someone outside the relationship, the impact is often deeply traumatic and disorienting. For many, it’s not just about betrayal, it’s about the collapse of everything they believed was true.
Understanding the impact of infidelity is an important step toward healing and rebuilding. It’s also important to understand that healing is possible, with work and the right guidance.
What Is Infidelity?
To understand why infidelity causes so much pain, we must first define it. Infidelity is the violation of a couple’s mutually agreed-upon expectations regarding emotional or physical exclusivity. What constitutes infidelity can vary between relationships. It’s definition may be explicit in regard to a physical affair, but less defined in terms of emotional infidelity or the "digital gray area", all of which could feel equally as damaging.
Understanding the definition of infidelity is one of the first steps toward recovery. People regularly ask me in my practice, “what is infidelity, really?” Is it just physical cheating? Or can an emotional connection without intimacy be just as hurtful? The truth is, infidelity takes many forms, and defining it clearly can help couples understand what went wrong and why it hurts so deeply. As someone who has personally worked with hundreds of couples battling with affair recovery, I believe that defining boundaries and expectations is crucial—not only in preventing infidelity but also in healing from it.
Infidelity is less about specific actions and more about the breach of trust. At its core it undermines the commitment and security that partners depend on in a healthy relationship. The pain caused by this betrayal can be overwhelming, leaving both individuals and their relationship in a fragile state. Rebuilding trust often requires a strong therapeutic relationship, which can enhance treatment effectiveness and support emotional wellness.
Why Infidelity Hurts So Deeply
Infidelity doesn’t just damage the relationship with our partner - it breaks the narrative of trust, safety, and identity that couples build over time. Many clients enter therapy believing they’ll never be able to move past the pain, unsure if healing is even possible. Surviving infidelity feels impossible not only because of what happened but because of the deep psychological wounds it leaves behind.
The Neurobiology of Betrayal
When someone discovers a partner’s betrayal, the brain processes it similarly to experiencing trauma. Stress hormones like cortisol and adrenaline spike, triggering the fight-or-flight response. It isn't uncommon for betrayed partners to experience panic attacks, intrusive thoughts, or sleepless nights. The brain begins to associate the relationship—a place once tied to comfort and love—with danger and uncertainty.
These emotional responses are not irrational overreactions; they’re the body’s way of alerting a person to a threat. Betrayal is a psychological injury, and recognizing it as such allows for more compassion and effective treatment during recovery.
The Lies We Tell Ourselves
One of the cruelest consequences of infidelity is the internal narrative it creates. Betrayed partners often internalize the event, asking damaging questions like:
“Was I not enough?”
“Did I miss the signs?”
“What does this say about me?”
At the same time, the betraying partner may minimize the event or justify their behavior to avoid guilt (“It was just one time” or “It didn’t mean anything”), which can cause further emotional harm. Marriage therapy for infidelity helps slow down these thoughts and reframe the situation through fact-based dialogue, empathy, and accountability.
The Lingering Aftershocks
Long after discovery, infidelity can affect daily life:
Difficulty concentrating at work
Emotional detachment from children or friends
Sudden outbursts of anger or sadness
Paranoia and obsessive “checking” behaviors
Without therapeutic intervention, these symptoms can persist for months—even years. This ongoing emotional toll is why many couples seek marriage therapy for infidelity in Tampa Bay and St. Petersburg. Effective treatment doesn’t just aim to repair the relationship—it helps each individual regain their emotional security and identity.
Dr. Perleoni’s 5 Pains of Infidelity
1. Betrayal of Trust - Trust is the cornerstone of any healthy relationship. When infidelity occurs, that trust is shattered. Partners often feel blindsided, questioning everything they believed about their relationship. The sense of security and safety that trust provides disappears, leaving feelings of vulnerability and fear.
2. Emotional Rejection - Being cheated on can feel like the ultimate rejection. The betrayed partner may feel they weren’t "enough", not attractive enough, not attentive enough, or not fulfilling enough. This can lead to feelings of inadequacy and a profound blow to their to self-esteem.
3. Loss of Identity - Infidelity forces individuals to reevaluate their relationship and, often, themselves. For many their identity is tied to being a partner (boyfriend, husband, wife, girlfriend, etc.). When infidelity happens it can create an identity crisis, causing individuals to ask themselves "Was my relationship a lie? Who am I outside of this partnership?".
4. Grief and Trauma - Discovering infidelity triggers a deep sense of loss. Betrayed partners mourn the relationship they thought they had, the future they envisioned, and the love they believed was mutual. The emotional toll can mirror the effects of trauma, including symptoms such as anxiety, depression, and difficulty trusting others.
5. Power Imbalance - Infidelity often creates a power imbalance in the relationship. The cheating partner holds the secrets, while the betrayed partner feels powerless and left in the dark. This imbalance can intensify feelings of resentment and emotional turmoil. Often these emotions and roles can flip as time passes. The betrayed partner may hold the events and built up resentment over their partner.
The Role of Couples Therapy in St. Petersburg and Tampa
Couples therapy in St. Petersburg offers a safe space to heal after infidelity, rebuild trust, and determine the future of a relationship. Therapists help couples explore the root causes of infidelity, such as unmet needs or communication breakdowns, fostering deeper understanding.
Therapy also facilitates honest communication, allowing both partners to express feelings and rebuild trust in a judgment free environment. Establishing clear boundaries, improving transparency, and setting expectations are essential steps in recovery, especially when guided by a licensed therapist.
Forgiveness and growth are vital to healing, and therapy supports couples in navigating this complex process, helping them rebuild emotional resilience and strengthen their relationship. Through structured guidance, therapy offers a path to transformation and renewal.
How Infidelity Impacts Mental Health and Traumatic Stress Disorder
The emotional toll of infidelity isn’t limited to the relationship itself. Both partners often experience significant mental health challenges in the aftermath. Young adults, in particular, may face unique mental health challenges such as depression, anxiety, and self-esteem issues following infidelity.
For the Betrayed Partner
Anxiety and Hypervigilance: Constant worry about whether it will happen again.
Depression: Feelings of sadness, hopelessness, and loss of self-worth.
Trust Issues: Difficulty trusting the cheating partner or future relationships.
For the Cheating Partner
Guilt and Shame: Overwhelming feelings of regret and responsibility for the pain caused.
Fear of Judgment: Worry about being labeled or condemned by their partner and others.
Loss of Connection: Struggling to repair the emotional bond they’ve damaged.
Why Some Relationships Survive and Others Don’t
Not all relationships survive infidelity, and that’s okay. Whether a couple chooses to stay together or part ways often depends on several key factors. First, both partners must be willing to commit to the healing process. Without mutual effort, reconciliation becomes nearly impossible. The depth of the betrayal also plays a significant role; a one-time mistake is often easier to forgive than a prolonged affair involving lies and deception.
I often find the state and health of the relationship before the affair matters. Couples with a strong foundation and healthy communication may have a better chance of recovery, while those with pre-existing issues may find that infidelity becomes the breaking point. Professional support can also make a critical difference. Working with a therapist trained in affair recovery (including specialized training like Systematic Affair Recovery Therapy), such as those specializing in couples therapy, provides the tools and guidance necessary to navigate the complexities of rebuilding trust and moving forward.
Steps Toward Healing
Whether or not a couple stays together, healing from infidelity requires effort, reflection, and time. Here are an experienced infidelity therapists tips for moving forward:
Acknowledge the Pain
Both partners must acknowledge the depth of the betrayal and its impact. The cheating partner must take responsibility for their actions without defensiveness or minimization.
Open Communication
Discussing the infidelity openly is painful but necessary. Transparency helps rebuild trust, while avoiding blame and focusing on understanding promotes healing.
Seek Professional Help from a Licensed Mental Health Counselor
Working with a licensed mental health counselor can help couples navigate the complex emotions and challenges that come with infidelity. Therapists can also provide tools for rebuilding trust and fostering forgiveness. If you are in the Tampa or St. Petersburg area, we offer free consultations to help you start your journey to healing.
Focus on Self-Care
Both partners should prioritize their mental and emotional well-being. Self-care activities, such as exercise, meditation, or journaling, can help individuals process their feelings and regain a sense of balance. Learn more about self-care here.
Rebuild Trust Slowly
Rebuilding trust is a long process that requires consistency, honesty, and patience. The cheating partner must demonstrate their commitment to change through actions, not just words.
Decide the Future Together
Healing doesn’t always mean staying together. Some couples may find that ending the relationship is the healthiest choice for both parties. Therapy can help navigate this decision with clarity and compassion.
Moving Forward
Infidelity is one of the most painful experiences a relationship can face, but it doesn’t have to define the future. By understanding "what is infidelity" and the emotional damage it causes, couples can begin the journey toward healing, whether that means rebuilding their relationship or finding peace apart.
If you’re struggling with the aftermath of infidelity, seeking "couples therapy in St. Petersburg" can provide the guidance and support you need. At It Begins Within Counseling, our experienced therapists are here to help you navigate this challenging time with compassion and evidence-based techniques. Together, we can work toward clarity, healing, and a brighter future.
