Much of what doesn’t make sense about good people who make the dark choice to betray their partners can be understood by delving into how our brain chemistry works. Neurologists use a term called neuroplasticity to explain the changes in our brain as a result of our experiences and knowledge. As licensed counselor Deborah S. Miller, LPC, writes in her book More Than Sorry, “…understand that in the context of an affair, the brain stirs up dopamine, serotonin, oxytocin, prolactin, and testosterone. These hormones contribute to impulsivity, poor decision-making, and intense energy, emotions, and feelings of possessiveness.”
A secret relationship can trigger the same kind of response as substance abuse, gambling, or other addictions. We can become “addicted” to infatuation and to the attention from a potential love interest. Once the brain pathway is established for the kind of pleasure that a secret relationship brings, then be on the lookout for the cravings. When the cravings take over, we lose touch with logic as we are carried away into impulsive adventure like an adolescent. We are more likely to judge reality in egregiously biased ways when we lack understanding of our brain chemistry.
Other biological factors may also have an influence on our risk for having an affair. For example, one survey found that those with an ADHD neurology, which comes with a weaker prefrontal cortex, are even more likely than the general population for a physical affair. Further, a 2019 study found that men with higher levels of testosterone were more likely to cheat than men whose testosterone levels were lower.
While our biology doesn’t define us or definitively determine our actions, our own brain chemistry plays a huge role in the decisions we make and can actually cause us to cheat ourselves from our inner knowing. Awareness of this is an important first step in protecting oneself (and in many cases healing from) the madness that lust creates and the deep trauma that infidelity causes.