As a doctor with a quarter of a century of working with couples, I have a unique insight into what causes infidelity and betrayal. And what makes love work.

In my 25-plus years as a licensed California therapist specializing in sex and intimacy, I have witnessed a great deal of pain. I have worked globally as an expert in the treatment of compulsive and addictive sexual behavior and I fully understand the dynamics that play out when chronic cheating is revealed to an unknowing partner. In a long-term, supposedly monogamous relationship, learning your partner has secretly been sexual outside of your relationship can create devastating consequences.
Having helped countless couples heal their shredded relationships and families after the crisis of betrayal, let me state a clear and undeniable truth: When you pledge fidelity to your partner and then violate that promise, your lives and relationship will likely never be the same. Even if your actual cheating never comes to lighttrust me, people with secrets act differently than those who are intimate. And to my point, very few people lie as well as they think they do.
As Beyoncé says to Lady Gaga in the video Telephone, “You know, Gaga, trust is like a mirror. You can fix it if it’s broke, but you will always see the crack in your motherf***ing reflection.” Truer words were never said.
But let me state clearly that my profession requires me to meet my patients without prior judgment or prejudice regarding their romantic and sexual choiceseven the bad ones. In fact, part of my job is to encourage fearful individuals to explore their sexual desires, as long as the resulting sexual behaviors are non-abusive, legal, and consensual.
Get your unlimited Newsweek trial >
Gender fluidity? Kink? Polyamory? Bring them on and explore away. Deeply embedded in both my training and personal values is the belief that shaming people for their healthy, naturally occurring sexual desires is not only cruel, it fails to produce change.
As a sexologist, it is not my job to tell a couple that they must be monogamous. That is their choice to make. Or not. If they choose monogamy, my job is to help them negotiate their relationship boundaries and to help them find resolution if/when those boundaries are broken. If, on the other hand, a couple wants an open relationship, my job is to help them create and commit to a set of rules that will protect their intimate bond from the influences of their outside sexual activity. No judgment, just solutions.
Get your unlimited Newsweek trial >
Having worked nearly half my life with families damaged by infidelity, I want to share three simple rules to help couples successfully negotiate monogamy, to avoid the pain associated when one partner cheats and to assist those struggling to overcome sexual betrayal.
1. Accept that cheating occurs when one spouse deliberately lies about or keeps meaningful secrets from the other.
In an age where things like porn and webcams are no further away than your digital device, many people wonder if those behaviors are really cheating? They ask: Is chatting up people on apps and flirting on social media a form of cheating? What about sexting? What if you never meet, physically engage, or learn the name of the other person? Is that cheating? I developed my definition of cheating to create some clarity about what cheating looks like in the digital age. Using my definition, cheating is less about specific sexual behaviors and more about lies and secrets used to cover up those behaviors. And, as just about every betrayed partner I’ve ever worked with has told me, “It’s not the sex that causes the most pain. It’s that I no longer know who my partner is or trust anything that he/she says. How can we have an intimate connection when there’s no trust?”
2. Don’t do anything outside the relationship that you wouldn’t feel comfortable communicating honestly to your partner.
If you want to use porn, sext, or otherwise be sexual outside your primary relationship, no problem, just ask your spouse if it’s OK first. If your partner fully and openly consents to whatever it is that you want to do, then you’re not cheating when you do it. But if you act on your desires without asking and receiving permission, you are cheating. Sure, I understand that no-one wants to ask their partner if its OK to have sex with other people.
But if the choice of “doing what you want first and then asking permission later” is going to lead to secrecy, lying, and the destruction of relationship trust, then I’m going to pick truth and honesty every time.
3. When making important choices, put your relationship before yourself.
The best way to avoid poor relationship choices, like cheating, is to ask yourself, before you act, is this a good decision for my relationship? When you view your in-the-moment thoughts and desires through the lens of what is best for your relationship, you set the stage for the kind of intimacy and contentment that many of us strive for. Making important decisions based on what only you want in the moment, however, may lead to short-term fun, but ultimately long-term misery and regret are likely to lie ahead.
Three Final Thoughts About Love
Love is not about words; love is about action. If I can no longer believe what you say because you lied to me and kept important secrets, then my trust in you can only be restored by your actions. Your words have lost meaning.
Human beings are built to pair-bond. We are created to love and nest with one another. Substantial research tells us that we are typically happier, healthier, and more successful when we’re in a loving relationshipas opposed to being single or in a difficult relationship. Thus, I wonder why any of us would ever want to screw up a good thing when we have it.
People who love you and are willing to put up with you full-time are quite rare and should be cherished. Many people never find that precious significant other. If you’re lucky enough to meet someone who brings meaning and love to your life, the wisest thing you can do is to use honesty and integrity to guide your intimate decisions.
Robert Weiss PhD, LCSW is chief clinical officer of Seeking Integrity Treatment Centers. He is an expert in the treatment of adult intimacy disorders and related addictions, most notably sex, porn, and relationship addictions. A clinical sexologist and practicing psychotherapist, he is the author of Prodependence: Moving Beyond Codependency, Sex Addiction 101, Out of the Doghouse, and Cruise Control, among other books. His podcast, Sex, Love, & Addiction, is rated as a Top 10 Addiction Podcast.
All views expressed in this piece are the writer’s own.