"Once a cheater, always a cheater." "People cheat when they're unhappy at home." "If your mate cheats, you'll know." We've all heard these bits of conventional wisdom; they're comforting, in a strange way. But they're all wrong, say the experts who study infidelity. What's worse, believing these myths can do a lot of harm, because it gets in the way of your preventing, spotting, and recovering from infidelity. (Yes, recovering -- contrary to popular belief, an affair doesn't have to destroy a relationship.) We've unraveled the latest research so you can protect your relationship with the facts.

The reality: With the right trigger circumstances, anyone is susceptible to cheating. "There are as many different profiles as there are people who have affairs," says Douglas Snyder, Ph.D., a couples therapist and a professor of psychology at Texas A and M University. Yet the myth persists that there's a recognizable "type" of person who's unfaithful. That's why it took Linda Mitchell, 43, a personal trainer in Monroe, OH, by such surprise when she found out her first mate was having an affair. "He never did anything to lead me to think he would cheat," she says. "He'd bring me flowers, tell me how beautiful I was and what a great partner I was."

While some people are chronic philanderers, it's more common to unintentionally wind up in an affair. "People who have accidental affairs have no thoughts of being unfaithful," says Snyder. "It's not even consistent with their values system, but the opportunity presents itself." Maybe a coworker hits on you during a business trip when you're stressed, or your cute handyman compliments you when you're getting over a fight with your mate.

"Here's the best way to prevent affairs: Rather than saying, 'We will never have one,' instead think of the kind of person, situation and mood that would make you vulnerable," says Barry McCarthy, Ph.D., a marital therapist and author of "Getting It Right This Time: How to Create a Loving and Lasting Marriage." Maybe you're so nurturing that you'd be vulnerable helping a neighbor whose wife just died, while your fun-loving sister would be susceptible during a trip to Las Vegas. It may feel contrived or scary, but having this tough conversation with your partner can help you both recognize chancy situations and be on guard.

You can also stay in safe territory with friends of the opposite sex by not confiding personal things, like airing complaints about your mate, and not keeping anything about those friendships secret. "You know you've crossed a line if you don't want your mate to know about whatever you're talking about with this person," says Tina Pittman Wagers, Psy.D., a clinical psychologist and instructor at the University of Colorado at Boulder. "If it starts feeling like that, then you need to pull back and reestablish closeness with your mate."

The reality: While baby-boomer men do cheat more, women in their 20s and 30s have affairs just as frequently as men their age, according to new research. One reason: More women are working. When you have a job, you've got more financial freedom, which could make you more comfortable taking a gamble with your relationship. You also have opportunity; around 46 percent of women and 62 percent of men who have affairs cheat with someone from work.

The reality: Michael, 34, a lawyer in Tampa, says his wife started having an affair before the couple's two-year anniversary. "I never, ever thought that would happen," says Michael. Yet the so-called honeymoon period is actually a high-risk time for infidelity. "More people have affairs the first two years of marriage than any other time," says McCarthy. Women may experiment with a comparison affair: Would I be better off with this guy? Did I make a mistake in marrying my spouse? Men, on the other hand, are likely to cheat for reasons that have nothing to do with their relationship. Thanks to their upbringing or their circle of friends, they may believe that's just what guys do.

An early affair may be just a last fling that a couple can work through, but it's more likely a wake-up call to a person that his or her partner has a fundamentally different model of monogamy, says Wagers. Still, newlywed affairs don't have to spell doom. If both partners decide that they want to give their union another shot, it's important to figure out what factors contributed to the affair and whether there's any hope for changing them.

The reality: It's true that the majority of women who've had an affair reported being physically and emotionally disengaged from their partners for at least a year before the affair. But more than half of men involved in affairs reported being happy or very happy in their marriages prior to cheating, according to a survey by the late Shirley Glass, Ph.D., noted infidelity researcher and author of NOT "Just Friends." Lots of other factors weigh into a guy's decision to start an affair, including chemistry, opportunity and poor impulse control. "I counseled a couple where the husband's younger coworker made a pass at him when they were at a conference and he accepted," says Wagers. "Even though he felt close to his wife and he felt like he had a good marriage, he was excited and flattered that this woman who was 15 years younger found him attractive."

Many cheaters do blame their actions on a less-than-perfect home life, but researchers say they're just rewriting history. "Often times these are retrospective reports that are now having to justify how it is that the partner violated vows," says Snyder. Granted, lots of cheaters are unhappy on some level in their marriages. But so are many men and women who don't have affairs. "Infidelity isn't the only road," says Wagers. "If you're not satisfied in your marriage, you might also be driven to talk to your partner." That's why therapists say it's so important to stay in touch with each other. For you, that might mean setting aside 20 minutes every night to talk about your day, your differences and your dreams. "It's the whole idea of staying close to your spouse," says Wagers. "The more disconnected you get from the relationship, the easier it is to slide down the slippery slope of infidelity."

The reality: No matter how blissful they feel, affair pairings rarely get to happily ever after. A whopping 75 percent of affair partners who marry end up divorced. For one thing, the qualities that attract you to an affair partner -- like impulsiveness or extravagance -- might be the polar opposite of what makes you happy long-term. And during affairs, lovers are under the spell of chemical changes in their bodies that make them feel euphoric -- feelings that are exaggerated even more by the secrets they're keeping. They're in a type of fantasy world, focusing only on each other and not getting bogged down in day-to-day stuff like bills and child rearing. "Somebody may seem like a soul mate when it's all fresh and shiny," says Wagers. "But you can't assume the new-car smell is going to last 15 years."

The reality: In many cases, the betrayed mate is totally in the dark. "A lot of cheating partners are really invested in keeping this secret and are very good at lying," says Wagers. So true, says Dayle DeCillo, 39, a mother of five in Mission Viejo, CA, who had zero suspicion that her husband of 11 years was unfaithful -- until she discovered him with another woman. "I was blindsided," she says. "He was a paramedic and firefighter, and was gone a lot, either 'working' or 'working out.' I was never concerned he wasn't where he said he was."

DeCillo simply made the same assumptions most people do: You assume you're trustworthy and your mate is, too. The possibility that he could stray isn't even on your mind, so you don't get suspicious if he says he has to work late or go on a golf trip with his buddies. Usually it's not until the affair is out in the open that the betrayed mate can go back and give new meaning to history.

It's also common after an affair is exposed for the betrayed mate to feel like he or she is facing a new truth: You never can be sure whether your partner will cheat. In reality, it's a truth that was there all along.

1. Be each other's number one confidant. You shouldn't be sharing private thoughts with others that you're not sharing with your mate.

2. Make time to connect on a regular basis. Daily moments of connection help you build a sense of togetherness and shared purpose.

3. Don't let family time squeeze out just-the-two-of-you time. Relationships that are too child-centered are at high risk for an affair.

4. Recognize when you're temporarily attracted to someone else. It doesn't mean there's something wrong with your relationship -- or that you have to act on it.

5. Surround yourself with people who believe in you and your relationship. If you're ever tempted and don't feel like you can tell your mate, you'll have someone else to confide in who will steer you straight. And if one of you does stray, you'll have a strong support network to help you put your relationship back together.