When it comes to why people commit financial infidelity, there are many reasons. “One partner might earn more than the other and feel that they don’t ‘need’ to disclose receipts or investments,” Olson explains, “another might feel a lack of control in the relationship, and exert themselves via secret purchases; someone else might be unhappy with their partner’s attitude towards money and want to splurge on themselves.”

While financial infidelity can, obviously, have calamitous consequences for a couple’s finances, the act of lying – particularly if it’s about a significant amount of money – can also lead to feelings of distrust and betrayal, potentially harming the relationship as much as, or more than, actual infidelity.

Thirty-four-year-old Niamh* from Belfast found out that her husband Terry’s* financial infidelity had caused him to rack up nearly £50,000 worth of gambling debts. As well as draining his daughter’s savings account, Terry has also been lying about his earnings, shaving £10k off what he actually earns and betting away £3,000 per month of the concealed amount. According to Niamh, he was able to hide everything fairly easily because he “came into the marriage with a small amount of debt”. Because of this, the pair decided to keep their finances separate – Terry paid rent and bills, while Niamh paid expenses – meaning neither had access to the other’s accounts.  After Terry was promoted at work, Niamh pushed him on applying for a mortgage, but after a heated back-and-forth, Terry finally made the admission about his debts.

Gambling is a particularly tricky form of financial infidelity, as it carries a considerable amount of societal shame and can often develop into addiction. According to a 2020 survey, up to 2.7 percent of adults in the UK are problem gamblers, but just three percent of those affected seek help. The problem particularly impacts men, who are seven and a half times more likely than women to develop an unhealthy gambling habit – whether it’s hidden or not, this can be damaging for finances, familial and romantic relationships, and the sufferer’s mental health.

Furthermore, as well as having a detrimental impact on relationship quality, Emily Garbinsky, an associate professor of marketing at Cornell University and another co-author of the 2019 study, says financial infidelity can produce “a negative feedback loop”. She explains: “The more frequently someone engages in it, the more the relationship suffers, subsequently making one even more likely to continue hiding financial behaviour from their partner.” To avoid this, Garbinsky advises that couples “specifically set aside time to discuss finances each month – akin to a financial date night”.

Although she had a previous financial transgression, since Louise’s £10k debt was discovered, she hasn’t lied about money since. “The problem hasn’t recurred because we regularly have [conversations]. about our finances,” says Paul.

For those on the other side of the problem – hiding spending or debts from their partner – Olson says the best thing to do is not just to come clean, but to plan the conversation ahead of time. “Talking about money can be very stressful, so planning a specific time and place helps each partner prepare,” she explains. “Remember, you’re in this together, so it’s not about ‘you vs me’, it’s about ‘us’.”

For all its sins, social media can often provide a safe haven for people to sow the seeds for these IRL conversations. Informative posts on TikTok and confessionals on Reddit are not only bringing awareness to the phenomenon – and putting a name to it for many – but are opening up a much-needed space for perpetrators and victims to anonymously share their stories and seek advice, and do so without shame and stigma. With any luck, this encourages more people to be honest with their partner and more honest with themselves.

*Names have been changed

For those struggling with debt or gambling, you can seek help via charities including StepChange, National Debtline, or GamCare.