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Whether it's in sport or board games, nobody likes a cheater but they are the absolute worst when it comes to relationships.
According to Statistics Brain at least 41 per cent of people in marriages have admitted to infidelity, signifying that this is a bigger problem than is usually acknowledged.
One thing that we often forget about when we hear about adultery is that there is another person, who might be fully unaware that they are seeing someone who is married.
It's not always their fault - the person committing the infidelity could have hidden any traces of their other life from their new partner.
Luckily if you do suspect that you are seeing someone that has commitments elsewhere, there are three vey easy ways to tell.
Australia Private Investigator Lachlan Jarvis has been investigating affairs for 35 years and has shared his discoveries with the Daily Mail.
The first tell-tale sign that Jarvis warns people to look out for is someone's age.
People over the age of 40 have been found to be the most likely to cheat due to a change in their own psyche over time.
The decisions that someone makes in their twenties or thirties can conflict with their wants and needs in their forties, leading to doubt and regret.
This goes hand-in-hand with the previous sign of adultery.
People's emotions change as they get older and they can often realise the person that they decided to marry didn't turn out to be "the one". They could get bored, or their libidos could diverge.
After realising this, they choose to cheat rather than to divorce or talk to their partner - which isn't really the best way to address the issue.
During his years of investigating Jarvis has found that he is frequently sent to snoop on individuals from conservative religious sects.
These people have often been part of the religion since birth and have abided by the followings all their life.
This can lead to them being pressured into a marriage at a young age, which later turns to bitterness, regret and then infidelity.
HT Daily Mail
More: Cheaters honestly explain how infidelity starts