Why Do People Cheat in Happy Relationships? Experts Weigh In
James Austin
Updated on February 23, 2026
Along with anger and sadness, therapists say confusion is one of the most common emotions people grapple with after discovering their partner has been unfaithful. And it's only natural to wonder why someone would cheat, particularly if the relationship seemed rock solid.
"Infidelity in a relationship may not mean that a partner is entirely miserable or that they want the relationship to end," explains Stacy Thiry, a licensed mental health counselor at Grow Therapy.
Ultimately, relationships are complicated. Just as someone can be miserable in their relationship and not cheat, so can the reverse be true, according to Aurisha Smolarski, a licensed marriage and family therapist and author of Cooperative Co-Parenting for Secure Kids. "Often, it's more about that person's unhappiness with themselves than the relationship itself," she says.
Here are a few reasons people might cheat even in happy, seemingly healthy relationships.
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1 They have low self-esteem.
"Low self-esteem leads to feelings of emptiness, disconnection, shame, guilt, and worthlessness," says clinical psychologist Monica Vermani.
According to Thiry, people sometimes seek out external attention, affection, and validation to increase their feelings of self-worth.
"Even in a loving, happy relationship, a person might feel unattractive or experience body image issues," explains Ken Fierheller, a registered psychotherapist and owner of One Life Counselling & Coaching. "While their partner may reassure them that they find them desirable or attractive, being flirted with or approached by a new person may provide a temporary ego boost."
2 They're seeking a dopamine hit.
Research shows that new experiences trigger a release of dopamine—a brain chemical involved in feelings of satisfaction, pleasure, and motivation.
Hence, having sex with someone new could offer a rush of those feel-good chemicals, says Renée Zavislak, a licensed marriage and family therapist and host of Psycho Therapist: The Podcast.
"I recall a client who deeply loved their spouse but found themselves in an affair purely for the thrill of the new," shares Kristie Tse, a licensed mental health counselor and founder of Uncover Mental Health Counseling. "They weren't miserable or seeking to escape their marriage. Even in a fulfilling relationship, individuals might crave the excitement of new experiences."
For this reason, Thiry says it's crucial for couples in long-term relationships to keep seeking out novel experiences together to combat boredom.
RELATED: 6 Ways to Rebuild Intimacy After Cheating, According to Therapists.
3 They have mismatched sexual needs from their partner.
Sex drive can vary from person to person, and it can also fluctuate over time. Sometimes, when a couple has mismatched libidos, Fierheller says the partner with the higher sex drive may seek out ways to fulfill their needs outside of the relationship.
That certainly doesn't make cheating OK. But if someone feels consistently unfulfilled in their sex life, they may be more likely to slip up and take an opportunity for intimacy with someone else.
This is why Fierheller says it's so important to have regular, open, honest conversations about your needs and desires. The more you communicate, the more likely you are to find a middle ground when it comes to sex that works for you both.
4 They have unresolved trauma.
According to Tse, traumatic experiences from someone's past can also drive them to cheat. For example, if they witnessed infidelity growing up, it may have been normalized for them.
"People who are raised in a home where a parent cheated on their partner often repeat these patterns," says Vermani. "They may have difficulty trusting or believing that their romantic partner will be faithful to them."
Attachment issues can also come into play: Research has shown that people with anxious and avoidant attachment styles may be more likely to cheat.
But that's not to say someone can use trauma as an excuse for cheating.
"Therapy and counseling can be instrumental in addressing these deep-seated issues, fostering personal growth and healthier relationship dynamics," adds Tse.
RELATED: 4 Signs Your Partner Will Never Cheat, According to Therapists.
5 They're lonely.
Sometimes, a partner's frequent physical absence can be a motivating factor to cheat.
"If an individual's partner travels a lot, they might start feeling lonely," says licensed marriage and family therapist Rachel Goldberg. "Even though they have every intention of spending their life with their partner and understand that the travel might be temporary, they begin to open themselves up to external companionship to fill a void. This could happen either purposefully or by happenstance when the opportunity presents itself."
In these circumstances, the cheating often starts as an emotional affair rather than a physical one.
6 They have poor impulse control.
Impulse control is the ability to resist sudden urges and temptations—and some people are stronger in this area than others.
"For example, someone who used to get into bar fights or drink excessively to cope with emotional difficulties might cease those behaviors as they age, settle into a relationship, or have kids," says Goldberg. "However, they may continue to seek some sort of thrill and escape from the stressors they face at home, leading them to act out of impulse and cheat."
Fortunately, there are ways to improve impulse control through therapy—such as by working on increasing one's capacity for empathy.
Rebecca Strong Rebecca Strong is a Boston-based freelance health/wellness, lifestyle, and travel writer.Read moreFiled UnderCheating • Relationship AdviceSources referenced in this article- Source: Trends in Neurosciences: Novelty and Dopaminergic Modulation of Memory Persistence: A Tale of Two Systems
- Source: Heliyon: The interplay of attachment styles and marital infidelity: A systematic review and meta-analysis
- Source: Cleveland Clinic: Impulse Control Disorders
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