IF Hollywood rom-coms are anything to go by, the only way to catch an unfaithful partner is putting on a naff disguise and walking in on them in the act.
But these days, you're far more likely to discover your partner's infidelity by hacking their social media accounts - or, as one woman unfortunately found out, spotting "unusual activity" on their FitBit in the middle of the night.
Earlier this month, NFL correspondent Jane Slater revealed how she'd caught an ex-boyfriend cheating when their synced exercise devices informed her that he was, erm, "active".
Sharing the horror story on Twitter, Jane joked: "Spoiler alert: he was not enrolled in an Orange Theory class at 4am.”
Although extramarital affair website Ashley Madison claims that cheating tends to lessen during the festive period, January sees a boost of 12 per cent more members - and 15,000 Brits on average sign up every month.
Do you suspect that your other half is being unfaithful? Here are five tips on how to catch them in the act... or if you're the cheater, avoid getting caught.
Alexa, play a recording of my partner fooling around
If you're still umming and ahhing over what to buy your (suspected) adulterous partner for Christmas, buying them an Amazon Alexa or Google Echo may just catch them in the act.
It’s not only useful to find out the weather and to play music around the house, but these nifty AI devices can be set to record voices and keep a record of all their commands.
To catch your other half out, book a weekend away and tell them it’s for work or a girly getaway.
Then, if you’re lucky - or rather, unlucky - they’ll invite their side piece to the flat and Alexa or Echo will record their voices.
Alternatively, one American woman discovered her partner was being unfaithful when she innocently checked the device's recordings of past commands.
Taking to Facebook to expose her partner's cheating, the woman raged: "Who knew Alexa recorded everything you ask to do? Because I f**king didn't.
"Just checked the history and sure enough, heard his s**** asking her to 'play love songs' in my living room while I was away with the kids."
How to check voice recordings on Amazon Alexa
Set up a fake Tinder account and get swiping
If you suspect your partner is back on dating apps, then chances are it's Tinder.
And if watching countless re-runs of Catfish has taught us anything, it's how to set up a convincing fake profile of our own.
Option one: Set up an account with sexy photos of a friend that your partner has never met and write a sultry bio. Set your distance and location to match your partner’s.
Option two: convince your pal to match with him on the app, get them to send you screenshot you photos of the conversation before breaking up with them once and for all.
Or, if you’re feeling vengeful, have a bit of fun with them through your friend’s account first... did someone say a Gucci belt?
One woman who knows a little something about exposing Tinder's love rats is single mum Erin Colleen, who has been cheated on in several relationships.
After downloading Tinder to get herself back into dating, Erin - who has a background in data mining - was horrified by the number of married men saying they were "looking for something discreet" in their bios.
Using her investigative skills, Erin then tracks down their partners on social media and informs them of what their other halves have been up to behind their back.
In fact, Erin is so keen to out cheating love rats that she purposefully swipes right on Tinder when she suspects her match might be in a relationship - and claims she can track down her Tinder match's other social media profiles in under an hour when she only has their first name.
She said: "I can't stand cheaters, I've been cheated on in the past.
"It was devastating to learn he'd been doing it right under my nose for years and nobody ever said anything to me about it.
"Whenever I see a profile that says 'married or 'looking for something discreet', I immediately swipe right to see if I can out the guy."
Scour the Cloud for answers and dirty pics
Let's be honest, most women simply have a gut feeling when they start suspecting their partner is being unfaithful.
“If your partner refuses to be transparent over passwords, they may have social media or email accounts they don’t want you to know about,” a spokesperson for Ashley Madison told Fabulous Digital.
“A healthy relationship is one where such information is freely shared. Having two phones is a classic ruse, where someone keeps a second phone private to be used for their secret life.
“Some people have one phone but different SIM cards, which offers the same secrecy.”
That said, most people tend to forget that once they’ve said yes to saving documents and photos to the Cloud through their smartphone - meaning it often happens automatically.
If your partner refuses to be transparent over passwords, they may have social media or email accounts they don’t want you to know aboutAshley Madison spokesperson
Track their movement and scope out strange locations
There are two steps to this trick; first, you need to find out what the login code is for your darling’s iOS phone.
Once you’ve got it, turn on the ‘Find My Friends’ app and send a request from your own phone to track their location and press accept.
Just turn the notifications off, so your other half doesn’t find out what you’re up to...
Then, wait until your lover ends up in a strange location, like a residential area – not their house – on a Wednesday at 3am or when they leave the office in the middle of a workday.
Grab your night vision goggles and head over there ASAP. (Disguise optional.)
Last October, an American man actually divorced his wife after she caught her cheating on Google Maps street view.
The man was trying to plan the best way to complete his journey to get a popular bridge when he spotted someone who looked familiar and realised it was his wife cuddling another man on a bench.
Despite the photo dating back to 2013, he angrily confronted his wife over her past infidelity. The couple later divorced after she admitted to having an affair.
Slide into your partner’s DMs
Texting is so 2010 – nowadays, people are turning to Instagram and Facebook to pick up strangers.
Although it's most people's first thought to check direct messages, you can also look for smaller clues.
Like that mysterious woman whose photos your boyfriend keeps commenting on and "liking".
On Facebook, type in your partner’s mobile number in the search bar and see if any duplicate profiles come up, and check your ‘recommended friends’ too.
His fake profile might very well be lurking in plain sight.
THE PRICE BEFORE XMASSingle mum spends £400 on festive extras for son BEFORE Christmas
AMAZON-INGMum 'traps' Elf On The Shelf inside Alexa - and he tells daughter to go to bed
FASHION FAILWoman skips Xmas party after Boohoo jumpsuit resembled a 'melted glitter ball'
NO SLEIGHRich kid horrified when family fry their £15 Xmas dinner to save money on bills
PAINFUL TRUTHGraphic photos show what endometriosis would look like if the pain was visible
MY REGRETSMy boy died of meningitis hours after docs said he was 'milking it'
For more relationship stories, this "princess" bride threatened to CANCEL her wedding over her fiance's "ugly" dress and hair choices on Don't Tell the Bride.
And this wife issued her husband with a VERY strict set of rules for his mate's stag do - including no booze and phone trackers.
Plus this man was hailed "The One" after he removed his girlfriend's fake eyelashes and labelled them "left" and "right" when she fell asleep.