Affairs in film and television series are often portrayed as exciting adventures, fun and mischievous; a way of breaking free from oppression… a conduit to a joyful existence. Embarking on an affair can seem like a solution to marital difficulties that have led to boredom, depression, low self-esteem or intense loneliness.

The reality of the experience of an affair is almost always very different. The explosion of brain research in the last decade has shed light
on some of what actually happens physiologically. There are major changes in how the brain functions when one is infatuated, in love, and also when one is keeping a secret.

Falling in Love

Two major brain changes take place during infatuation.

The first is a flood of the neurotransmitter dopamine. One of the functions of dopamine is to heighten the sensation of pleasure. Dopamine also increases energy, hence that first animated, exciting conversation. Another interesting part of the dopamine response is that the next time one sees that person, before even talking to them, dopamine again floods the system. This person has now become associated with intense pleasure.

The second change is that the level of another neurotransmitter, serotonin, decreases. There are three effects associated with decreased serotonin levels that are important to understand here. The first is the subjective feeling of emptiness. The second is obsessive anxiety. The brain literally runs the person away from the emptiness towards the person who has become the object of the obsession. The third effect is sleep disturbances, which I’ll discuss later.


Let’s say these brain changes are resolved by going ahead with the affair. Now the hormone oxytocin floods the system. Oxytocin is associated with love. It is released during hugging, kissing, and cuddling and it makes you want to do these things more. It makes you more emotionally open in general, which is why many people during the earlier stages of affairs experience an enhanced sense of well-being and believe that the affair is good for them or sometimes even for their marriage. The more time spent with the affair partner, the more oxytocin is released, which again increases the desire for emotional intimacy with the person who is the object of the obsession.

Keeping the Secret

A part of the brain called the cingulate cortex is essential to our emotional responses. It is wired to tell the truth. The cingulate cortex signals other regions of the brain to share information so it can move on to more important functions, like planning and problem-solving. But when a secret is locked inside, the cingulate cortex is not allowed to perform its natural functions. Instead, the cortex becomes stressed and releases stress hormones, such as cortisol.

This is where the negative effects start to cascade. Increased cortisol levels negatively affects attention, memory, blood pressure, appetite, digestion, metabolism, and sleep to name a few.

Not getting enough sleep can lead to mood swings, depression, irritability, difficulty controlling one’s temper, and, when faced with a perceived threat, the “fight or flight” response. Physiologically, speaking, we can see why people in affairs can get angry or withdrawn when questioned about it by their spouses.  Interestingly, recent research also shows that lack of sleep decreases one’s capacity for empathy and makes people more self-involved emotionally.

Research also shows that the brain becomes desensitized to lying.  The first lies about infidelity are experienced as the most  stressful and guilt inducing.  This is related to the sometimes unbearable feeling of keeping a one night stand a secret from one’s spouse, even if the intention had been to do so.  However, if the encounter turns into an ongoing affair, which requires many lies, the brain adjusts and lying can come to feel like a matter of course.  For someone who has not engaged in much lying up until this point, this transformation can leave one feeling unrecognizable to oneself.  Once the affair is revealed, this sentiment is often repeated by the spouse.  I often hear, “I don’t know who you are anymore.”

The Antidote

What I have described above has many similarities to the physiological effects of addiction . The antidote to addiction is, of course, stopping and facing withdrawal. Withdrawal from a love relationship has been shown to be physiologically similar in intensity and quality to withdrawal from heroin.  No wonder so many people in unhappy relationships are afraid to let go.

But an affair is only an affair as long as it is a secret. Coming clean about an affair might mean disclosing it to one’s spouse.  Although this can be extremely painful, there can also be a kind of relief, even if it means facing extreme marital discord for a while, including the threat of divorce.  Another option is disclosing to a therapist where the costs, benefits and meanings of what has happened can be explored.

Once the affair is disclosed, the next step can become self-evident. This might mean ending the affair. It might mean living on one’s own for a while. It might mean ending your marriage. (Some affairs are unconscious attempts to do this.) It might mean talking with a therapist individually about what has happened to you and clarifying feelings and priorities. It might be an opportunity to explore issues in your marriage that you thought you could never address with your spouse, with a marriage counselor.

I have seen hundreds of individuals and couples struggling with these issues. If you are thinking that individual psychotherapy or marriage counseling may be beneficial and you live in the San Francisco Bay Area, please feel free to contact me at 925-948-0562 or at  If you live outside of the area, please visit my “Links” page for a geographical listing of therapists who are especially effective with affairs.