I’m not limiting cheating to men, but let’s be honest, Valentine’s Day is for women. If you forget to get your husband or boyfriend a present, he almost certainly won’t notice, let alone care.

This year, Valentine’s Day falls on a Sunday and coincides with the long President’s Day weekend, giving cheating husbands more opportunities to see his girlfriend. Here are a few suspicious signs to look out for on Mistress Day:

• Long absences or “plans with the boys”
• Unexplained charges or a bigger charge than you’d expect on his credit card bill (e.g. He bought you a small bouquet of flowers, but the charge on his credit card is for $100)
• He constantly checks his cell phone for messages or takes calls in the other room
• Changes in behavior (e.g. He acts much more affectionate or distant than usual)

Have an accomplice. Paul Young helped facilitate and hide the affair in a number of ways. From booking hotel rooms under his name to falsely claiming paternity of Edwards’ and Hunter’s love child, he was the perfect accomplice (until he wrote his tell-all book, that is).

Don’t call your lover with your regular cell phone. Incriminating text messages and call logs have been the downfall of many adulterers, most recently Tiger Woods. Edwards cleverly bought a cell phone that he used exclusively to talk to Hunter. He would then hand off the phone to Young so that Elizabeth could never stumble upon it. He and Hunter would also dial into three-way conference calls, scheduled by Young, so there would be no trace of her phone number on his call log.

Don’t leave written evidence. After the birth of their love child, Edwards sent Hunter flowers, but did not sign the card in his name in case someone saw it.

Don’t use your credit card. A credit card statement can be essentially a diary of a sloppy adulterer’s affair. When Edwards started paying Hunter’s living expenses, he made sure to send her cash and her own credit card through Young. He even managed to avoid using his own funds, funneling her money from wealthy campaign donor Bunny Mellon through an elaborate cover-up.

The most prominent recent example is Tiger Woods: After allegedly carrying on secret affairs with numerous women over several years, he was finally undone by text messages sent to Rachel Uchitel, the first mistress to be unveiled. A friend of hers told the National Enquirer about the affair, claiming she had seen incriminating text messages. The published rumors likely led to Tiger’s fight with his wife, Elin Nordegren, and subsequent car accident. For further embarrassment, another one of Tiger’s mistresses, Jaimee Grubbs, then gave illicit text messages incriminating Tiger to US Weekly, which then published them.

Most cheating spouses probably don’t have to worry about their “sext” messages being published in a tabloid magazine, but this story should still send shivers down a texting adulterer’s spine. It’s clear that as with emails, text messages can be retrieved. Even if both the sender and receiver delete the incriminating text message from their phone, communications providers like AT&T and Verizon store them for up to a few weeks.

According to this article in the New York Times, text messages are now considered proof of an affair in a court of law. Although cell phones are considered private property, if a cheating spouse’s cell phone is part of a family calling plan or often left unlocked and unattended around the house, a suspecting partner could legally be justified in checking the messages.

Myth #1: I wear a trench coat and fedora.
While on a surveillance case, a private investigator should dress to blend in with the location. So if I’m tailing a Wall Street type during the work week, I may wear a suit. Or if I’m tailing someone on a weekend, I may wear jeans and a baseball cap. Although I do own a trench coat, it is has yet to be part of my “disguise”. Since I’ve never had a case to follow someone to a costume party, I can’t imagine a scenario where dressing like Dick Tracy would help me blend in with a crowd.

Myth #2: My days are full of car chases, shootouts and other suspenseful activities.
I wish my days were as exciting as Magnum’s, although I’m pretty happy to skip the shootouts. The reality is that most of my time is spent running background reports and doing computer surveillance and forensics, which doesn’t exactly put me in the line of fire. But when I am doing surveillance, a typical case involves sitting in a car for at least 3-4 hours waiting for the suspect to emerge from a building door. This can get immensely boring. And unlike cop shows on TV, I don’t have a partner keeping me company, which brings me to the next assumption…

Myth #3: I have a sidekick.
Unlike Sherlock Holmes, I don’t have a loyal sidekick who goes with me everywhere, ready to help me get out of trouble or crack a case. Wouldn’t that be nice! I usually work alone, but on rare occasions may work with another private investigator for a particularly tricky moving surveillance case.

Myth #4: It’s easy to follow someone.
If you’ve ever followed a friend’s car to a restaurant or their house, you know how easily you can lose someone in a car. Maybe they blaze through a yellow light, and you get stuck as it turns red. Or maybe a minivan sneaks in between your cars so you miss seeing a turn your friend makes. So if it’s hard enough to follow someone who wants you to follow them, imagine how difficult it can be to follow someone when you don’t want them to notice you.

Myth #5: I have a tricked out car.
The last thing a private investigator wants is to get made, so driving a flashy, recognizable car like Kit from Knightrider would be an incredibly bad idea. For my moving surveillance cases, I drive a basic, nondescript sedan. If I conduct moving surveillance on the same subject multiple times, then I will use different cars on each day.

In an adultery investigation case, finding evidence like the email exchange between Cornell Business School employees “Lisa” and “John” would be like winning the jackpot. In case you haven’t already heard about the scandal, John accidentally copied the entire school on a very long and explicitly tawdry email exchange with his mistress Lisa. Both are married and, as is made abundantly clear from the email, engaging in a steamy affair. Read the full email transcript for the R-rated, torrid details.

Assuming this leads to at least one divorce, Lisa and John will need to hire top notch lawyers. With evidence like this, their spouses will not need to bother hiring a private investigator to prove adultery. Since the email was sent publicly, it should be admissable in a court of law. From the email, we know Lisa has children and, depending on New York’s divorce laws, this evidence may help her husband get custody.