4 'Subconscious Processes' That Motivate Infidelity

These four mental shifts are often a turning point for infidelity in relationships. Here's why they happen.

By Mark Travers, Ph.D. | February 24, 2025

Infidelity is often framed as an impulsive decision—a lapse in judgment or a moment of weakness. But in reality, cheating is rarely spontaneous. More often, it is preceded by a slow and subtle psychological process, one that allows a person to justify their actions before they ever step outside the relationship.

At the heart of this shift is a change in perception—where dissatisfaction is magnified, past happiness is rewritten and the relationship itself is reinterpreted to justify seeking something new. This isn't just about falling out of love, it's about reshaping the narrative of the relationship to make infidelity feel like an escape rather than a betrayal.

If you've ever wondered how someone can go from deeply in love to stepping outside their commitment, understanding this mental transformation is key. Here are four ways this process unfolds subconsciously.

1. Amplifying The Negatives

A key sign of shifting perceptions in a relationship is when a person suddenly starts zeroing in on their partner's flaws while minimizing or forgetting their strengths. The same quirks that once felt endearing now seem intolerable. Small annoyances that were once brushed off become proof of deeper relationship failures.

This phenomenon, known as "negative sentiment override," was identified by relationship expert Dr. John Gottman. It occurs when accumulated disappointments cause a person to filter even neutral or positive interactions through a negative lens. The brain, primed by past resentments, distorts reality—interpreting a casual comment as criticism or a neutral action as neglect.

Here's how you might reframe the same incident with and without this bias at play:

• Before negative sentiment overrides—"They forget little things sometimes, but they're thoughtful and always have my back."
• After negative sentiment overrides— "They never pay attention to me. I always have to repeat myself. I feel invisible in this relationship."

This shift isn't always deliberate—it's the brain's way of making sense of discontent. By rewriting the partner as the primary source of unhappiness, the person avoids confronting deeper internal struggles or external stressors that may also be contributing to their dissatisfaction.

2. Rewriting The Relationship's History

Once negatives are amplified, the next step is reinterpreting the past to fit the new perspective. This is where someone mentally revises the history of the relationship, downplaying moments of love and connection while emphasizing past disappointments.

This might sound like:

• "Honestly, I don't think I was ever really in love with them."
• "We were never truly compatible; I just didn't see it before."
• "I've been unhappy for a long time—I just didn't admit it to myself."

A 2000 study on memory bias in long-term relationships, published in Personality and Social Psychology Bulletin, shows that people don't remember their past accurately—they revise it based on their present emotions. A study tracking wives over 20 years found that their memories of the past became increasingly negative, even when their actual relationship experiences had not changed as dramatically. By 20 years in, their recollections of past happiness had faded, aligning more closely with their current (often lower) marital satisfaction.

Additionally, this process is driven by cognitive dissonance—the discomfort we feel when our actions don't align with our self-perception. If someone sees themselves as a loyal person but is drawn toward another relationship, their mind works to resolve the conflict.

The easiest way? Convincing themselves the relationship was doomed from the start. By reshaping the past, they make infidelity feel less like a betrayal and more like a natural escape from a relationship that was "never right" to begin with.

3. Shifting The Blame

One of the most critical steps in mental editing is displacing personal responsibility onto the partner. Instead of seeing infidelity as a personal decision, the brain reframes it as something caused by the other person's failures.

For example, this may sound like:

• "If they were more affectionate, I wouldn't feel this way."
• "They never make me feel special anymore—why shouldn't I find someone who does?"
• "I've tried everything, but they just don't understand me."

A 2024 study on moral disengagement sheds light on this dynamic. Individuals with higher moral disengagement tend to disconnect from their moral standards, viewing their actions as justified by their partner's perceived failures. This disconnection allows them to frame infidelity not as a personal decision, but as a response to their partner's shortcomings, making the betrayal feel less like a violation of trust and more like a natural consequence of the circumstances.

This shift serves two key purposes:

1. It reduces guilt. By portraying infidelity as a reaction to the partner's behavior, it becomes easier to justify the action, reducing feelings of guilt and framing it as something they were "driven" to do.
2. It avoids self-reflection. Rather than exploring personal emotional wounds, unmet needs or self-sabotaging patterns, the focus is placed entirely on the partner's flaws. This externalization of blame prevents the individual from confronting the deeper, more complex reasons behind their dissatisfaction.

Essentially, this step allows the person to feel like a victim of their circumstances rather than an active agent of their own actions.

4. Idealizing The Alternative

When someone begins to mentally "downgrade" their current partner, another person—whether a friend, coworker or acquaintance—can start to appear more attractive. This is where the grass-is-greener illusion takes hold. The brain, in its attempt to justify seeking something new, romanticizes the alternative:

• Current Partner. "We never have fun anymore. They always seem distracted."
• New Person. "They're exciting and full of life! They really listen to me."

This comparison is inherently flawed because the long-term relationship is being judged by reality—its ups and downs, the daily stresses and disappointments—while the new person is viewed through the lens of novelty, with only their most appealing traits in focus.

A 2017 study on job transitions reveals a similar pattern: when people change employers, they often experience a honeymoon effect—initially feeling more satisfied with their new job, only to see that satisfaction steadily decline as the novelty wears off. Similarly, the new person in a relationship is viewed through a lens of excitement, free from the day-to-day stressors and complexities of a long-term relationship. The "new" person hasn't yet been exposed to the complexities of a long-term connection, and their flaws have yet to surface. Over time, however, as the novelty fades, the initial allure will likely diminish as well.

How To Recognize And Stop This Process Of "Mental Editing"

If you notice this pattern in your relationship, here's how to break the cycle:

1. Challenge your thoughts. Ask yourself: Am I focusing only on their flaws? Have I stopped noticing the good?
2. Revisit your history honestly. Rather than rewriting the past with negativity, reflect on the full picture—including the moments of joy and love you've shared.
3. Own your feelings. Dissatisfaction often stems from unmet personal needs. Are those needs being communicated clearly to your partner?
4. Talk about it early. Don't wait until it's too late. Many affairs occur because people assume their needs won't be met, but this assumption is rarely tested through honest conversation.

Every relationship eventually loses the novelty high, and when that happens, the mind may search for explanations. It's rarely just "falling out of love" but often the result of a slow mental shift.

Take the science-backed Relationship Satisfaction Scale to become aware of your unconscious patterns and take proactive steps to preserve the foundation of true intimacy.

A similar version of this article can also be found on Forbes.com, here.