As experienced psychologists in private practice, we've watched relationships fall apart because of cheating.

The damage done when an affair is uncovered often feels like a tsunami washing over everyone intimately connected to the parties. Spouses, children, parents, other relatives, friends and work relationships all may be affected to varying degrees upon the revelation of an affair.

Although being able to discuss with your partner any interest in cheating is implicitly part of the marriage vow, in reality, it rarely occurs. It can just be too scary to seriously consider.

Most people instead prefer to soothe themselves with rationalizations about not wanting to hurt the other person. They also enjoy the fantasized bubble of excitement, anticipation and novel encounters filled with passion and ego enhancement.

Of course, bringing thoughts or fantasies into the open also means you risk being thwarted before taking action. Often the desire to cheat is stronger than the desire to be talked out of it. Talking about it makes it more real, and that means having to think about the heavy price you will pay in the emotional damage done to your partner and others — not to mention the financial and lifestyle consequences if the affair leads to separation or divorce.

As psychotherapists, we treat the devastation resulting from the discovery of an affair. We witness the shame, anger, rage, guilt, lies, emotional pain and chaotic rupturing of lives. What we hear repeatedly from partners who choose to stray is that they seriously believed their actions would never be found out.

Can you imagine how many might choose not to begin if they knew, beyond the shadow of a doubt, that they would be found out? How many might burst through the fantasy bubble that doesn't allow for thinking about consequences and pull back from the brink?

Unless you are conducting your affair overseas with a partner who doesn't know English or how to use a phone, text messaging or e-mail, the chances are that, at some point, you will be found out. So if you are thinking of having an affair, think again.

When you notice thoughts, fantasies, planning and flirting behavior, pull back and see these for what they are: signs that you are considering an affair.

Here are other indicators that can help you know you're vulnerable to an affair: frequently emphasizing your partner's faults while minimizing his or her strengths and arguing without resolution about small and large issues; purposely spending time away from home to avoid your partner; abusing substances as a way to self-medicate in an unhappy marriage; participating in chat rooms and starting online relationships that are kept secret from your partner; failing to communicate well or at all over months; withholding affection and sexual intimacy; and avoiding activities together.

If all the problematic issues leading to affairs aren't cause enough, keep in mind that people often have affairs simply because they can — not because they are unhappy in their marriages or relationships.

In fact, some will tell you they are quite satisfied with their partner and life but that they couldn't say "no" to someone who was persistent in his or her advances. As we have said, opportunity is the strongest predictor of affairs, with the need to prove one's desirability coming in a close second.

Finally, beware of the chemicals your brain secretes when you think about the excitement of an affair. These chemicals make it easy to ignore your good judgment. The most powerful antidote is to neutralize them by feeling the paralyzing fear that comes with knowing you will be caught — and everything that goes with that.

STEVEN and DEBORAH HENDLIN are clinical psychologists in Newport Beach. Read more at http://www.Hendlin.net.