How to catch a cheater

Trust Your Gut

"Ninety-nine percent of the women who come in to see me say that they had a gut feeling their significant other was cheating," says Danine Manette, a licensed private investigator and author of Ultimate Betrayal: Recognizing, Uncovering and Dealing With Infidelity. "But it takes them a while to act on it."

"Men will deny, deny, deny," adds Tom Martin, the president of Martin Investigative services. "But most of the people we're hired to follow are having an affair."

Checking In

Growing distant is an obvious sign of an affair; what's more difficult to detect (and cope with) is when the cheating partner starts becoming more attentive and loving. "It seems like they're calling you to say hi for no reason, but really trying to find out your whereabouts," says Manette. They're overcompensating to cover their tracks.

Get Outta Town

"We advise the wife to tell her husband that on Tuesday, she's going to take the kids to an amusement park, or the beach," says Martin. "Within 15 or 20 minutes of leaving, he's usually hot to make his own exit."

Web of Lies

Cheaters often take steps to hide their online footprint. Keep an eye out for password-protected files that you can't access. Another tech clue? "If the history on a browser is erased often, then your romantic chum may be hiding something," says Brian Taylor, the private investigator featured on the new AMC series Small Town Security.

Hot Rod

With so many affairs starting online, cheaters will often travel long distances to meet a lover in another city or town. Keep an eye on the odometer and "take note if they're filling up the gas tank more often," says Manette.

Sniff 'Em Out

If you and your partner are like most couples, then you probably know his habits better than your own. So if he starts coming home from the gym smelling freshly showered, when he usually smells like body odor, then something strange might be going on. "Use your eyes, nose, and ears to uncover potential shenanigans," says Taylor.

Excuses, Excuses

"Some people will say they have to work late on a Friday night, but will forget their excuse," says Taylor. "On Friday morning, the story will change, and they'll tell their wife that they have a friend in town who wants to have drinks. It's almost like they want to get caught."

Feeling Frisky

"If your partner gets more sexually experimental out of the blue, you know you may have a problem," says Manette. Oftentimes, it means that he's trying things with his lover that, given that you're also available to him, he might want to also try out with you.

Critical Thinking

"Cheating partners can often become more critical because they are comparing you to the other person," says Manette. "They tell you that you're gaining weight, or that you need to read more, or that your hair would look better short. They want to change things about you that were never a problem before."