Half of all people who cheat are eventually caught – for two main reasons.

Being wed to our phones as well as our partners, means most leave damning digital footprints which expose the truth.

The second red flag is a series of changes in behaviour that makes their partner suspicious or curious.

Worried yours is up to something they shouldn’t be? These are the eight most reliable indicators your partner is playing away.

1. THEY TAKE THEIR PHONE WITH THEM EVERYWHERE

This is the No 1 ‘I’m Cheating’ giveaway.

Even the most trusting person starts to think, ‘That’s odd’ when a partner who used to happily leave their phone lying around, suddenly has a near heart attack when you dare to pick it up.

Cheaters keep it with them, always. Even in the bathroom when they’re having a shower. They’ll swiftly swipe up if they see you looking over their shoulder or left to delete something.

Tracey Cox says that cheaters keep their phone with them at all times – even in the bathroom when they’re having a shower (stock image)

A study by US divorce lawyers revealed 81 per cent of divorce lawyers have seen an increase in cases hinging on social media and mobile phone evidence.

If you’re suspicious, look up deleted messages when your partner does leave their phone open (and if you’re really suspicious, google how to find and read messages that have been deleted. It’s remarkably easy.)

2. THEY INSIST ON PRIVACY THEY DIDN’T NEED BEFORE

They get twitchy if you sit beside them when they’re ‘working’ online. They start closing and locking the bathroom or toilet door, when they were perfectly happy peeing and showering with it open. 

They’re less forthcoming about the minutiae of their day. Talk less about the new ‘friend’ they made at work and couldn’t shut up about (be on high alert for this one: it usually means the relationship has moved from an emotional to a physical affair).

Relationships thrive on transparency and if you notice things like changed passwords, your partner not talking calls in front of you or changed levels of openness in general, pay attention.

3. THEY CAN’T KEEP THEIR STORIES STRAIGHT 

It takes a lot of planning and lying to hide an affair: one reason why most peter out eventually. It’s exhausting having to remember everything you said you did or didn’t do.

Sex and relationships expert Tracey Cox (pictured) warns that if a cheater asks a friend to cover for their affair, they are more likely to be rumbled

The longer the affair, the higher the chance you’ll see inconsistencies in their stories – especially if they know they’re being cornered. Research shows our memories are less reliable under stress.

The way to trip someone up, is to ask questions about what happened just before or after the event you think they are lying about. Most people rehearse a lie only to cover the period they were cheating. 

Ask what they had for lunch or dinner before or after the event. How busy it was on the road/how crammed the tube was. Stuff they weren’t expecting to be asked about. 

Simple questions can sometimes elicit giveaway clues. If your partner’s away at a ‘work conference’, ask, ‘How’s the weather there?’. It’s such an innocent question, most people immediately answer with the truth – answering ‘It’s pouring rain,’ when they’re supposed to be somewhere sunny.

4. THEY’RE DOING THINGS THEY DON’T NORMALLY DO

The sofa slouch that turns into a gym bunny. The guy who usually wears old scruffy jumpers suddenly switches up to a shirt and suit jacket.

Having new interest in improving their appearance can be a sign they want to look better and healthier for you… or are out to impress someone else. Major lifestyle changes are strong indicators of an affair when there’s no other obvious reason for them.

In order to catch a cheater out, sex and relationships expert Tracey Cox recommends asking your partner simple questions about their day (stock image)

5. THEY SEND THE WRONG MESSAGE TO THE WRONG PERSON

I had a friend who did this: sent the message intended for the lover she was just about see, to her husband.

It said: ‘You’re going to be inside me in under one hour’.

Considering her husband was at work and she was on a train to meet her ‘sister’, she might as well have texted, ‘Surprise! I’m having an affair!’.

Caught red-handed, she had the grace to not even attempt to wiggle her way out of it and they divorced soon after. Even a simple ‘I had a great time last night’ sent to the wrong person has been the downfall of many secret affairs.

6. YOUR LOCATION TRACKER REVEALS WHERE THEY REALLY ARE 

Back when things were rosy in your relationship, you both ticked ‘yes’ to letting location services tell each other where you both were at any time.

Years later, you’ve forgotten…..and caught out with a bald-faced lie. ‘I’m with a friend having a facial,’ you say when they call. ‘Really?,’ your partner answers, ‘I didn’t know pubs like The Queens Head offered facials’.

Thirty-four percent of people who caught their partner cheating discovered it through digital means like location-sharing apps.

7. THEY TELL OTHER PEOPLE WHAT THEY’RE UP TO

The minute you tell someone you’re cheating, you’ve told two people. Virtually everyone tells either their partner or a close confidante about a secret they’ve been told to keep – and they tell theirs.

One person quickly doubles and triples and before you know it, confessing to one person means a dozen people know.

Yet 72 per cent of people do tell at least one person about their infidelity – mainly because they want to talk about the person they’re either in lust or love (or both) with.

Rope in a friend to cover for your secret trysts and you’re even more likely to be rumbled – especially if they’re a friend your partner also sees.

If they don’t drop you in it, their partner will (‘Hang on, wasn’t that the day you helped your sister move?’).

Sometimes it’s intentional: they’ve promised not to tell but feel bad about it.

8. THEY’RE LESS AFFECTIONATE 

Another classic indicator of infidelity: your partner becomes emotionally distant or disconnected from you.

The reason why people withdraw is obvious – guilt makes it difficult to meet the eye of someone you are betraying. Or, if your emotional energy is invested elsewhere, your partner might now seem sadly lacking and not worthy of your love.

Whatever the reason, when someone who was once attentive, suddenly becomes far less so, something has shifted in their life.

Affair or no affair, this one needs to be addressed head on.

• SexTok with Tracey and Kelsey comes out every Wednesday. You’ll find Tracey’s books wherever you buy your books and info about her and her products ranges at traceycox.com.