The One Thing That Secretly Gives Away a Cheater According to a Private Investigator

It’s not lipstick on the collar or a second phone — it’s how they talk about their day.

When someone’s having an affair, most people think the red flags are obvious — secretive phone use, changes in routine, or sudden attention to appearance. But according to one UK private investigator, there’s a far subtler sign that can expose cheaters every time: a shift in storytelling patterns.

John Eastham, lead investigator at Private Investigations UK, says it’s all about how people talk about their daily lives — or more specifically, how they don’t.

“We’ve tracked hundreds of cheating cases, and one of the most consistent tells isn’t tech-based or physical — it’s verbal,” explains Eastham.

 “People having affairs tend to skip over parts of their day in conversation. They become vaguer, less linear, or even over-rehearsed when describing where they’ve been. It’s not always lies – it’s gaps. And those gaps matter.”

This change is rooted in psychology: when someone is hiding something, they subconsciously protect the “edited” version of events by avoiding open-ended questions and routine small talk. Over time, partners may notice:

• A lack of spontaneous detail in day-to-day stories

• Repeating the same phrases or “set” answers (e.g., “It was just work stuff”)

• Avoidance of reciprocal questions, so they don’t have to mirror the conversation

• An unusual focus on one 'alibi' detail, e.g., “I was definitely at the supermarket at 6.30” – even if you didn’t ask

You don’t need spyware – just listen better

Rather than checking phones or hiring a PI straight away, Eastham advises watching for behavioural gaps over time:

“Cheating isn’t always exposed through tech. Sometimes it’s what’s missing from conversations that reveals the truth. When someone’s no longer telling you the boring bits of their day, that’s when to start paying attention.”