How to Catch a Cheater

For anyone with a wandering eye, it’s easier than ever to find a new lover. At any moment, people hoping to cheat can swipe through a roster of potential hookups within a one-mile radius who are willing to snap dick pics, send dirty voice notes, or meet for a quickie. They can have emotional affairs and coordinate an illicit weekend getaway over Instagram DMs all while an unsuspecting spouse lies beside them in bed, unable to tell whether their partner is doomscrolling or sexting.

Our addiction to our devices may have an upside, though, when it comes to exposing infidelity. Instead of waiting by a landline to intercept a mistress’s call, suspicious partners can use apps, location trackers, and catfishing to confirm their worst fears. “There’s a digital imprint everywhere you go,” says Robin Martinelli, owner of the private-investigation firm Martinelli Investigations, Inc. “There are emails and text messages and people leaving their iPads and computers open.” Infidelity allegations make up 95 percent of her business, because in Georgia, where she lives, proven adultery can influence alimony awards in divorce cases (most private investigators I spoke with said these kinds of clients are split evenly between men and women). To gather evidence, some situations may call for higher-tech solutions, like a voice-activated pen or Ring camera, while others may be better suited to some gumshoe detectivework. I spoke with PIs, loyalty testers, and therapists about the trade secrets they use to suss out and prove an affair.

Is your boyfriend or girlfriend cheating? Look out for these patterns.

There’s a reason why “working late” has become a euphemism for workplace affairs. When someone is leading a double life, it tends to affect their routine. “It’s lying about where they’re going after work. It’s not coming home. It’s a change in their schedule,” says Marc Tropeano, a private investigator at LA Intelligence. “You live with these people. There are clear signs.” But a shift in routine isn’t the only tell that your partner may be cheating.

Pay close attention to aesthetics. Are they suddenly obsessed with toning their obliques? Are they wearing a new cologne? Do they primp for an hour before running an “errand”? Your S.O. may be trying to impress someone new. Martinelli says that one of her clients suspected his wife of cheating after she got “new boobs” without telling him. “It was a huge red flag for him,” she says. “They didn’t sit down and have a conversation about it. He went away; she had ’em done.”

Another warning sign is a change in sexual appetites. “Either they don’t want to have sex with you anymore, they want sex five times a day, or all of a sudden they want different sex,” says Martinelli. “Like, ‘Hey, the trampoline’s outside — let’s go have fun!’”

Monitor their digital habits as well. If someone changes their phone or computer password, is spending more time texting, or becomes defensive if you peek at their screen, they might have something to hide. It’s also common for cheaters to become more distant. Others may overcompensate by buying their partner gifts or acting overly attentive. Couples therapist Jean Fitzpatrick says that in addition to feeling guilty, the person might be trying to distract from the infidelity or trying to “remake a partner into someone he or she finds more desirable” by giving them stylish or sexy clothing.

Ultimately, you’re the best judge of your S.O.’s irregular behavior, says Tropeano: “You sleep with them. You know their sweat. You know their routines.”

Review shared bills for clues.

Cheating can be expensive. If you share a credit card with your partner, reviewing the statements can be a dead giveaway. Maybe they are spending more on gas, buying lingerie that you’ve never seen, or making long-distance calls to a number you don’t recognize. “It is very difficult these days to book almost anything without a credit card and ID,” says Don Aviv, president of the private-intelligence agency Interfor International. “Long gone are the days of paying for a hotel room or a flight with cash alone.” One of Aviv’s clients noticed suspicious transactions on his wife’s corporate-credit-card bill. When the man discovered that the charges were from an app called Dayuse, which offers short-term hotel stays, he decided to snoop on her phone. She had made dozens of bookings over the past year and had one planned for the next day. The man decided to show up in the hotel lobby to confront his wife. “They ended up going to the room she had booked and had it all out,” says Aviv. “She admitted to other affairs and trysts, and they spent a few hours crying and discussing their lives and marriage. She said she was glad she didn’t have to lie anymore.”

A cheater’s car can be a gold mine.

If your partner drives, their car may be littered with evidence of a tryst. “They put all kinds of stuff in there, like receipts or a go bag” for a hotel, says Martinelli. One of her clients discovered that his wife of 20 years had stashed a vibrator and a pair of underwear in the glove box of their shared vehicle. Martinelli sent both items to a crime lab and found they had traces of another man’s DNA on them.

If you can’t find physical proof wedged between the seats, the pros often use GPS tracking. The laws are murky, but in many states, anyone who owns or co-owns a vehicle can legally install a GPS tracker on it. You can stick the small device, which costs about $20 on Amazon, underneath the car and follow someone in real time from an app on your phone. Barbara Wolford, the owner of Kinsey Investigations, regularly installs GPS trackers on behalf of her clients (private investigators tend to have more legal rights when it comes to surveillance). She usually finds the model of the suspected cheater’s car first at a dealership so that she can figure out exactly where to place the device without tipping off the driver. Sometimes there are snafus. Wolford remembers one woman who followed her gardener husband to a worksite and panicked when she couldn’t find him anywhere. It turned out he was simply high up in a tree doing some trimming. But Tropeano says the technology more often provides an easy way to catch someone in a lie: “If your husband, Bob, is at a private residence in Santa Monica when he’s saying he’s at work in Downtown Los Angeles, now you have information.”

Spy pens may come in handy.

Want to channel your inner Sherlock? Digital surveillance options — ranging from Cheaterbuster, a website that scans a person’s dating-app history, to smoke detectors with hidden cameras — can help you figure out what’s going on with your partner. Important to note: Not all of these methods are legal and could land you in court or on an episode of Dateline. If your partner is litigious, they could sue you just for looking at their phone, as Tom Sandoval recently did to Ariana Madix before dropping the suit. Aviv suggests hiring a professional PI who has access to investigative databases and knows the law. But other PIs think there are tools the average person could use.

Wolford has told multiple clients to plant a voice-activated pen, which ranges in cost from $20 to $130, in their home or car to pick up on illicit conversations. She says one man used the device to catch his wife telling a colleague about what her boyfriend “does to her in bed.” Is this aboveboard? Wolford admits that it’s not since most states require that one person involved in a conversation consents to the recording. But if someone wants to validate their suspicions rather than gather evidence for a custody battle, she says the device might still do the trick. If illegal surveillance doesn’t sit right — which, fair enough! — Martinelli suggests installing a security camera outside your house. That’s how one of her clients discovered that her husband would call his girlfriend from the back porch in the middle of the night. “He’d be on the back porch, smoking a cigarette, going, ‘Hey, honey. I love you. Can’t wait to see you this weekend.’” Martinelli then put a GPS tracker on his car and discovered the mistress was his wife’s best friend.

Be your own Harriet the Spy.

Sometimes it’s best to catch a cheater the good old-fashioned way. Tropeano prefers to follow people by car, which he says the average person could do. (No high-speed chases or distracted driving, please!) He suggests people rent a vehicle that their S.O. won’t recognize and snap a photo if they catch suspicious behavior.

Since many people cheat with a colleague, multiple PIs also suggested surreptitiously showing up to your S.O.’s workplace. A few years ago, one of Martinelli’s clients became suspicious that her husband, who is a doctor, was cheating when he started blowing off their lunch dates. The woman decided to covertly walk by the hospital cafeteria, where they usually met, and on two occasions found him eating there with a female colleague. It turned out they were having an affair.

Hire a loyalty tester.

Not everyone is looking to prove their S.O. cheated. Some people just want to know if their partner would cheat when given the opportunity. If you fall into this category, you can pay a loyalty tester less than $100 to professionally catfish your S.O. Trinity Howard fields requests on social media and on an app called Lazo from roughly 20 women a week who suspect their boyfriends have a wandering eye. “I think they want reassurance,” she says. “As in, Okay, I have a bad feeling about him, but I need to make sure that he is doing something before I get up and leave.”

And what better way to find out than to ask a gorgeous 22-year-old blonde to slide into your partner’s DMs? Howard takes a casual approach since “most guys will get sketched out if you just come on strong.” She’ll ask, “Hey, do I know you?” or say they matched on Tinder in the past to try and build familiarity. A small percentage of guys immediately shuts her down, but roughly 70 percent take the bait. She’ll make small talk, send photos of herself, and ask whether they’re in a relationship. Then she pops the big question: “Do you want to meet up?” All the while, she’s texting their partners with real-time updates. One guy even sent her photos of himself in the shower and asked her for nudes while his girlfriend was in the other room.

Of course, you could always do the catfishing yourself. One of Aviv’s clients created a fake Tinder profile of an ersatz man whom his wife agreed to meet up with. But there’s also an entire app filled with loyalty testers to choose from, and Howard says having some emotional distance from the cheater makes it easier to dupe them: “If they do it themselves, I think it comes across as more fake.”

Or simply ask them, “Are you cheating on me?”

While cosplaying as a spy may seem thrilling, don’t overlook the simplest solution: Just talk to your partner. “People know when they’re being cheated on,” says Tropeano. “Yet there’s an insatiable lust to prove it beyond a reasonable doubt.” Unless you need evidence for an expected legal battle, Tropeano often suggests clients talk to their partners first, especially if they want to stay in the relationship. Some cheaters may deny the accusation, but others might be relieved to have the conversation. “You’d be surprised at how often a partner will want to talk,” says Fitzpatrick. “Living a double life is hard for most people, and sometimes they’re ready to put it out there.”

Fitzpatrick says the key to confronting your partner is to stay calm. Schedule a time to talk rather than angrily bringing up cheating allegations at 2 a.m. when you can’t sleep. Do something sensory beforehand, like exercising, cooking, or listening to music, to quiet your nerves. And begin the conversation in a nonaggressive way, known in therapy-speak as a “soft start-up,” so that your partner isn’t on the defense. “You say, ‘Look, I have some real concerns about our marriage. I’m wondering if there’s anything you want to tell me?’” Fitzpatrick suggests. “There’s been dishonesty in the relationship, and what you’re trying to do is create honesty.” Of course, if your partner becomes angry or tries to gaslight you, by all means put on your detective hat.