Why so many people are cheating on their partners right now.

More Australians are cheating on their partners right now than at any other point throughout the year.

According to cheating website Ashley Madison, the period between December 21 and March 20, marks their highest number of signups. Last year, the site says more than 130,000 affairs began over the three month period.

This, of course, begs the question: Why?

Interestingly, on the other side of the planet, cheating also sees a surge during summer.

Dr Tammy Nelson, a sex and relationship therapist, says “Increased levels of serotonin are associated with more exposure to sunshine, ultimately allowing people to feel happier.

“With more sun exposure in the summer people will feel more confident, and this could help kick start someone’s decision to start and extra-marital affair, allowing them to feel better about the decision.”

According to evolutionary psychologist Daniel Kruger, the rise in affairs is also due to the simple fact that during the warmer months, people tend to socialise more.

There are, in his words, “increased chances to be unfaithful.”

A survey published by Ashley Madison also found the reasons why adulterers say they sought a new relationship.

Sophie Monk speaks to Mamamia about cheating. 

The number one reason was somewhat unsurprising: Sex.

But many said they weren’t driven by a desire to replace what they already had. Rather, 24 per cent said an affair was an attempt to keep their marriage in tact, while five per cent desperately wanted to experience butterflies.

Dr Nelson says this isn’t unusual. “Many people cheat to stay in their marriage,” she explains, “they do it because they want to keep their family together.”

Interestingly, 39 per cent of respondents said they were “looking for friendship” in an affair, while 41 per cent of women said they were craving affection.

According to Luke Athens, a private investigator for Heartbreakers, a company that has been uncovering infidelity since 1996, there are a number of signs to look out for when it comes to a cheating partner.

Speaking to Mamamia, Athens says travel can often be the biggest indicator.

“Travel often tells all. If you suspect that your partner is lying about where they have been an easy way to check is noting the kilometres of the car. This reveals if they are driving a different distance than they usually would, or if they’ve snuck out during the night or at a time they said they’d been home,” he explains.

“Checking their Opal card (public transport card) statements also shows what suburbs they are travelling to and exactly where they hop on and off. Another great statement to check is their toll account.”

Often, Athens says, rubbish bins can be seriously incriminating.

“Check their rubbish. Bins often hide a lot of clues about what someone has been doing and where. If there’s a receipt from a dinner for two at a nice restaurant, or an empty packet of condoms, these clues can give you a good indication of someone’s activities.”

Sudden changes in schedule can also indicate the possibility of an affair, as well as strange purchases on their bank statement.

“Cheating partners will often need to purchase condoms,” Athens says, “men are likely to buy Viagra and women a bottle of wine so items like these should stand out if you pay particular attention.”