1. Don’t write anything in an email that you hope to keep private.

If you’re going to have an affair, avoid engaging with your lover over email—we don’t live in the You’ve Got Mail/AOL era anymore. You may think sending emails from anonymous accounts or saving them in a random folder may be a surefire way of keeping the liaison a secret. But as we’ve seen in the case of Gen. David Petraeus, email is never as private as you think. The now-former CIA director and his alleged mistress, Paula Broadwell, often wrote each other saucy email messages. But near the end of the affair, a third party was unwittingly involved when Broadwell, through various anonymous accounts, sent “harassing” messages to Petraeus’s friend and colleague Jill Kelley.

Kelley apparently was disturbed enough by the messages—described as “cat-fight stuff” to The Daily Beast by a source close to the matter—that she reported them to a friend in the FBI. The ensuing investigation reportedly traced the messages to Broadwell, and then the illicit relationship with the general. Petraeus and Broadwell tried to conceal their affair by composing messages to each other in the Drafts folder of a shared Gmail account, which only made matters worse, given that it’s a method often used by terrorists. But this whole email fiasco could easily have been avoided. (Note to cheaters: don’t share passwords with a lover, particularly a jealous one.)

2. Communicate furtively on the phone.

This one’s a no-brainer. You know you’re not going to be able to resist the temptation to exchange salacious voicemails and texts with your lover, but the chances of your significant other seeing them on the kitchen counter while you’re taking the trash out are too predictable. You can still communicate via phone without getting caught, however. Try using a rogue pay-as-you-go phone, i.e., not your work phone or the one that you usually use to call a spouse. If you want a backup system, get yourself an Android phone and download the Secret SMS Replicator, an invisible application that forwards all text messages to another phone (your rogue phone, if you’re smart).

3. Develop a cheating “strategy” and make it your new religion.

If you’re going to conduct a clandestine relationship, do it like a pro. Keep an internal list of excuses and make sure to rotate through them. If you use the “working late” excuse too often with a spouse, that spouse might contact someone else at the office to see if you were really there until 2 a.m. Similarly, if you make a habit of leaving work during the day for a quickie, try to avoid using the “doctor’s appointment” card too often. A skeptical boss might ask for a note, a bill, or a simple explanation, in which case you might be tempted to feign a chronic illness and get tongue-tied in your own elaborate lies. Pay attention to detail and make rules for yourself. (Rule 1: Always shower after seeing your lover.)

4. Make time for cheating.

Be smart about the time you spend with your lover, as though you had taken on a new hobby or a part-time job. The “hobby” is a good excuse for leaving the office at a certain time every day or getting home late, but make sure you have something to show for it. If you’re heading to or returning from a biweekly Tae Kwon Do lesson, it would help to have a few moves in your back pocket so you don’t look like a deer in the headlights when you get hit with, “Honey, show me what you learned in Tae Kwon Do tonight.”

5. Perfect your poker face.

If you’re going to cheat and not get caught, it has to be like second nature for you. So if your spouse is feeling unloved because, well, you’ve been putting all your energy into “Tae Kwon Do,” give him or her some good loving—and get used to acting like you’re into it.

6. Always pay with cash.

One easy way to cover your tracks is to pay for anything involving your lover with cash, whether it’s a hotel room, a fancy dinner, or a sex toy. It’s the best way to ensure that illicit activities don’t show up on your credit-card statement, which might end up in the hands of a spouse or an accountant.

7. Don’t screw around with someone at work.

If the head of the CIA couldn’t get away with it, chances are you won’t either. Having an affair with someone you work with is risky business—even if you’re not a politician or a public figure. For starters, your colleagues likely know you’re married, so they might end up tattling on you if they have the slightest suspicion you seem a bit too cozy with your boss. An office affair also makes the “I’m stuck at work” excuse more likely to backfire.