20 signs your partner is cheating, according to a private investigator

• Most people would rather know they're being cheated on instead of living a lie.
• Some people go so far as to hire private investigators to find out the truth.
• According to one top private investigator, cheaters often follow the same patterns.
• In his book, Tom Martin highlights 20 signs your partner is being unfaithful.
• They include more obvious signs like returning home late, to less cliché ones such as having a short temper.

Finding out a partner has cheated is never easy — but most people would rather know the truth than remain in the dark about their significant other's infidelities.

To catch an unfaithful partner in the act or confirm suspicions, people turn to the experts; private investigators, who make it their life's work to uncover hidden relationships and illicit affairs.

As the ones that hunt down cheaters, private investigators know all of the signs that indicate someone is hiding something — or someone.

We spoke to a top private investigator — a former federal agent — about the obvious signs someone is cheating, as well as the lesser-known red flags, and when it is time to panic.

Tom Martin told The Independent that cheaters always follow the same patterns.

Having seen identical signs over the last 40 years, Martin, the president of Martin Investigative Services in Newport Beach, California, wrote the book "Seeing Life through Private Eyes," where he lists the 20 most telling clues that may indicate infidelity.

And while they seem pretty obvious, he says that spotting one or two of them isn't a reason to worry. However, if you spot four or more, it is practically an admission of your partner's guilt, according to Martin.

The most common and obvious signs, he told us, are the ones such as spending longer hours at work, business trips, less sex, or defensiveness.

A new commitment to the gym or new clothing may also be a sign your partner is working on bettering themselves — possibly with someone else in mind.

Noticing just one or two of the signs on the list may not mean a partner is necessarily guilty, as all relationships go through change — but "if you have three or four, you have a problem," he told us.

However, one of the most important signs, one that you should not ignore, is intuition, according to Martin — as people can typically always tell when a significant other is not being 100 per cent truthful.

1. Changing habits
2. Leaving the house early and returning late
3. Business trips
4. Holiday or family event absences
5. Excessive overtime
6. Unexplained spending
7. Secret accounts (Instagram, email)
8. Hidden credit card bills
9. Extra grooming
10. Scent of someone else (typical lipstick on the collar)
11. Buying gifts you haven't seen
12. Unexplained items — condoms in the car are a giveaway
13. Joining a gym
14. Missed calls from an unknown number
15. Coded or secretive text messages
16. Less sex
17. Evasiveness or defensiveness
18. Obvious lies
19. Prickliness or short temper
20. Hate surprise visits (your unexpected arrival may come at an inopportune time for a cheater)

Even if a partner isn't displaying any of the typical signs, your feelings may be picking up on something.

Now, in the era of technology, Martin told us that most people are able to confirm their fears themselves — and no longer rely as much on private investigators to do the digging.

"The game has changed drastically," Martin said. "And technology is 100 per cent the reason why."

According to Martin, the signs are all the same, but catching someone is now as easy as picking up a phone or logging on to an iCloud account.

After seeing a significant other sneak away for a late night phone call or hide a text message, people are now "catching them themselves," he said.

However, Martin warns not to panic in these situations or jump to conclusions — as it can "jeopardise a valuable relationship over what may be unfounded anxieties."

If you do have an inkling that your significant other is cheating, looking for four or more of the signs may put your mind at ease. Or you can call in the experts.

Join the conversation about this story »

NOW WATCH: A diehard Mac user switches to PC