People who have been cheated on warn about one key sign that probably means your partner is being unfaithful

People who have been cheated on have warned others of the one 'key sign' they may be missing, which could mean their partner is being unfaithful.

In some people's eyes, cheating is the ultimate act of betrayal - and something that would instantly end a relationship.

With a new form of cheating on the rise and many divided on what actually counts as cheating nowadays, it can often be difficult to spot the signs your other half is being deceitful.

A number of social media users have since commented on a Reddit thread that asked: "What’s the biggest 'they’re definitely cheating' sign you ignored?"

While one mentioned their partner would change their phone password every week because of 'security reasons', there was one sign that seemed to be brought up time and time again - and it involves a bit of reverse psychology.

People who have been cheated on took to Reddit to detail an obvious sign (Getty Stock Image)

One Redditor wrote: "Constantly asking where I was and accusing me of cheating lol. I worked 12+ hour shifts at a remote oil plant. When the f*** was I getting time to get some d*** on the side? I had to strategically plan grocery shops."

A second added: "Bizarrely accusing me of cheating with no reason, evidence, or provocation."

While a third remarked: "Accusing me of cheating, when it never even occurred to me to cheat."

And a fourth quipped: "He got paranoid and kept wanting to check my messages. I thought it was insecurity. He was talking to a mutual friend about moving across the country with her."

Some people work solely on catching cheaters out, including Cassie Crofts, whose job as a private investigator involves uncovering cheaters on a daily basis.

The Australian runs Venus Investigations and works with clients who are concerned their partner may be cheating and conducts dating background checks.

Cheating can sometimes be hard to catch (Getty Stock Image)

Speaking with UNILAD, Cassie discussed the process of catching cheaters and it begins with going through a timeline with the concerned partner.

"We try, wherever possible, to sort of identify a particular date where we think something's going to happen," she said.

"Like, you know, he's flagged a couple of days in advance that he's going to be working late, or there's a trip to go see his cousin and you've never heard of this cousin. What's going on, that kind of thing."

Cassie continued: "I sort of build out an investigation plan for them based on what's a successful outcome. And then we talk through costings and how long we're willing to do this for, and they get a daily update on where things are at.

"So occasionally it will have been three days [and] we haven't found anything, and they're like, 'Look, at this point, it looks like he's doing everything he says he is. We'll call it there'.

"And some people want to keep going a bit longer. There's always that conversation with the client around you know, 'it's been two weeks'."