He’s married, and he looks at another woman. She, with a husband and two kids, lunches alone with a single male coworker. Does this behavior amount to cheating? What about text messages and phone calls?

In the television series Orange Is the New Black, Piper has sex with Alex, another prison inmate, while Larry, Piper’s fiancé, waits in the outside world for Piper to finish serving her time. Does it make any difference that Piper and Alex are female while Larry is male? Did Piper cheat?

What is cheating anyhow?

Different people view cheating differently. It may be tempting to believe that “everyone knows” what is right. Alternatively, you may believe that “he’s known me long enough”—or she has—“to know what I think.”

Don’t kid yourself. Clarity is essential. Otherwise, in moments of crisis, the two of you will disagree about what has happened. “What you did was wrong!” “It was not. How can you say that?”

You both need to know what to expect. Is exclusivity a given? What sort of contact with exes is okay? Do you object to my having friends of both genders? (How do these rules play out for gays and lesbians?)

What text and phone contacts make you uncomfortable? What boundaries will help us protect our relationship? What happens if one person has a change of heart?

Start here: “I want you to promise me that if you decide you don’t love me anymore, you will tell me before you pursue someone else. I don’t want to be blindsided. Okay?” Once both of you see eye to eye, then if one person reneges, the other person can say, “I thought we had an agreement about this. What happened?”

Cheating amounts to a fundamental violation of trust, without which two people cannot get really close to each other. The terms on which trust is extended will vary from person to person and couple to couple, making it extra important to identify them up front so that both parties feel comfortable sharing sensitive information.

An agreement about the extent of your commitment to each other can set your mind at ease. This benefit is important. Even constant checking offers no guarantee that someone has not cheated.

If you feel compelled to check and can’t stop, consider: the issue is not his behavior but yours. You have not finished grieving some past losses. If you have been badly hurt before, you may be working overtime to keep from being let down again.

Repeated checking only reinforces your anxiety. Worse, if you disregard your partner’s protestations of innocence and continue to search for evidence of misdeeds that never happened, eventually your mate may adopt a “what’s the use” attitude and look elsewhere for romance. Then you will have brought about the very thing you wanted to avoid.

In relationships, it is always important to start from a presumption of honesty. A presumption of dishonesty invites deceit.

That said, let’s say he betrays you by sleeping around. What should you do? Anytime you face a crisis, a big loss, or great pain, ask yourself: “What do I need to do to take care of myself?” Resist the temptation to try to fix him.

Focus on you. If you don’t meet your own needs, no one else will, and until you do so, you have little to offer anyone else. Be your own best friend.

You will be stuck with the consequences of your actions, whether or not they meet your expectations. You picked a partner who cheated, and the responsibility for dealing with the problem remains entirely yours even though you didn’t deserve it.

Cultivate an inner voice that supports and guides you. Throw out any old tapes from the past that tell you you aren’t worthy, you aren’t smart and capable, or you shouldn’t trust your own judgment. Take a can-do attitude. Tap into the energy of your anger.  If all else fails, have faith.

Institute a calm, loving voice that cheers you on, congratulates you on your achievements, and helps you pick yourself up and move forward after dismal, embarrassing failures that reawaken old feelings of shame. This voice offers guidance, helping you learn from your mistakes.

To decide how best to proceed when your partner has cheated on you, ask yourself whether the behavior seems to be within his or her control. Consider the following examples.

  • You and she, married, have been having problems for some time. You fight often and over trivial things. You have little or no sex. For that matter, you don’t even have fun together. She is angry or silent and uncommunicative. You have just discovered that she recently slept with a man she met at a professional conference. This behavior is clearly out of bounds. You learn, furthermore, that there have been one or two other dalliances in the past few years.
  • You and he are married. You are pregnant. You learn from peculiarities with credit card bills that he has been having unprotected sex with strangers, including escorts and streetwalkers, for many years and on a weekly basis. He has concealed this information from you and denies it until you show proof.

As the first case suggests, some people cheat even though they know they are jeopardizing a long-term relationship. Usually they do so because they feel unheard by their partner or afraid to tell their partner what they need and aren’t getting.

When communication is blocked, cheating can be a maladaptive way of expressing anger and resentment. Also, nothing beats a crisis for getting someone else’s full attention. Counseling can help both parties learn to listen and understand each other more fully.

On the other hand, some people seek sex compulsively. This scenario suggests addiction and an underlying mental health issue. Change can occur only if the sufferer—the addict—takes appropriate action. It is out of your control. The circumstances of case 2 hint at compulsive behavior.

Only a foolish adult would stay hitched to someone who was reliably a danger zone.  On the other hand, you don’t want to blame another person for infidelity that hints at communication issues, since both people created the problem.

Once you have sized up the situation, you must consider what is best for you. What risks and harms do you face if you stay and if you go? Don’t let your desire for the other person, or your denial, overwhelm your judgment. Don’t evade the issue by telling me about your unconditional love for your cheating partner. Unconditional love exists only between parents and children.

Your want to make the wisest decision you can on your own behalf with the information available to you. Ideally you will look back at some future time and feel you did the best you could. If taking action to protect yourself seems difficult or impossible, consider: can you hold yourself accountable for your decisions? If you can’t, you will be your own worst enemy.

Protecting yourself means trusting no one more than, say, 90 percent. You must always have a Plan B. Trusting no one at all, however, would mean never taking risks.

No one ever triumphed, in love or in life, without risking failure in the process. We must all accept and move beyond past betrayals in order to build muscle for future challenges. Periodic disappointment is just the price of eventual success.