The media depicts a world where married couples seem incapable of being faithful to one another. It is a world in which lying to someone you love and cheating is glorified, sexy and exciting, while the wonders and awesomeness of a being in a deeply connected and committed relationship with your soul mate is boring.

The topic of infidelity grabbed the headlines in a big way when the Ashley Madison website was hacked. After a study found that 91 percent of adults considered extramarital infidelity wrong, we learned that millions of married people were registered on a website the sole purpose of which was to facilitate breaking one’s marriage vows by having casual sex with strangers. We think it is wrong, but do it anyway?

Sex therapist Esther Perel defines fidelity not by sexual exclusivity, but by the strength of a couple’s commitment to one another. While I personally have no interest in a so-called open marriage, I agree with Perel that the primacy of the couple’s emotional bond should be paramount in a marriage.  With this perspective, emotional boundaries are critical for maintaining the level of trust and intimacy necessary for a marriage to succeed through all of life’s many challenges. Infidelity, including emotional infidelity, is about breaching that trust.

With the Internet, there are so many new ways to breach your spouse’s trust that do not involve having sex with someone else or even physically being with them.  Violating the emotional boundaries essential for maintaining a great marriage is even more damaging to a relationship than violating physical ones.  So couples should identify and consider these emotional boundaries and keep them sacrosanct. Violating physical boundaries is terrible, but crossing emotional boundaries is even worse, and it’s harder to repair.

Here’s what I mean.  How many times have you fallen in love? For most of us, there are handful of times in our lives in which we truly give our hearts to another human being in the romantic sense. It is a sacred act that is the greatest gift we can give another person.

Yet how many times have you given your body to someone? My guess is that for most of us, we’ve shared our bodies with considerably more people than we’ve shared our hearts through real love. Which would hurt you more: learning that your spouse had sex with someone else purely out of lust, or that he told someone else that he was in love with her? While neither is a pleasant prospect, the latter is a more serious betrayal of the soul bond that makes up a marriage.

When you get married or make a life commitment to someone, you give what I call the romantic part of your heart to that person. You open up yourself to the highest level of vulnerability by loving someone. He gives his heart to you, and the two of you commit to only share certain things with one another. It is a sacred bond. A sizeable part of your heart is designated only to him. (Other parts are for your parents, children, and friends, but the love you feel for these people is very different from the love you feel for your spouse.)

Whenever we give that romantic part of our heart to someone outside our marriage, we are taking something from our spouse that we promised to him alone. Presumably, this is done without our spouse’s knowledge or consent. It is a breaking of this important emotional boundary and commitment we gave our spouse–a boundary and commitment that is the essence of our marriage.

When we begin breaking down this emotional boundary to give that part of our heart to someone else, we are playing with fire at the expense of our spouse and our marriage. Unless your spouse is pretty out of it, he will feel that a part of you that was there for him is gone.  He’ll notice something is missing when you are together, even if he can’t put his finger on exactly what that is. Crossing the emotional boundary into infidelity involves creating some degree of emotional unavailability on the part of one spouse that interferes with the relationship as a whole. It is toxic to your relationship with your spouse.

Someone asked me whether I thought a person could be in love with two people at the same time. I believe the answer is yes, but you can’t love two people at once with your whole heart because you are dividing it. You cannot be a wholehearted person and give your love in a complete sense to more than one person at a time.

This is why we play with fire when we look up old flames on the Internet, friend people on Facebook because we think they are hot, or flirt with someone by text, email or any other form of communication. If you want to see what your college boyfriend is up to nowadays out of curiosity, that is one thing, but to begin communicating in an intimate way to see whether he still has feelings for you is courting trouble. When we do this, we are using these people for external validation—to make us feel good about ourselves. (This is a form of emotional childhood, and you can read about that HERE.) It is a big red flag that you’re doing something wrong.

We may think such behavior is innocent, but this is a rationalization. Intimate love relationships can and do start this way. On some level, it is easier to fall for someone through Facebook and email because you can each pretend to be whomever you want, and don’t have to smell that person’s bad breath in the morning or pick up their dirty underwear that missed the laundry basket. These connections made away from the front lines of reality can become emotional affairs before you even realize what is happening.

So many people convince themselves that this behavior is okay because it makes them feel good, is exciting and doesn’t involve having sex. If you have to hide it from your spouse, however, that means it is time to get your conscience out of mothballs and take a good, hard look at why you are hiding this.  How would you feel if your spouse were behaving this way? Is it really worth destroying your partner’s trust in you and acting without integrity to get that external validation?

You can learn to love yourself so that you don’t need to get romantic attention from inappropriate sources. The benefits of this are powerful. Read more here.