When 48-year-old site manager Valerie* left her husband, she cited lying about money as a reason for their relationship dissolution during their divorce proceedings. She tells Mashable, "He had never cheated on me, as far as I know, in a sexual or romantic way or anything like that. But he lied to me and betrayed me in ways worse than I could ever imagine."

She continues, "he hid letters from our mortgage provider, our bank, and all our utility companies from me. They were all in his name and he was the bill payer because he earned so much more than me, and didn’t tell me when we went into arrears."

The worst part for Valerie, she says, was that they’d fallen back on their rent payments because he was spending the money on a gambling problem. "I found out when I came across debt collection letters in our kitchen by accident and confronted him. It had been going on for almost a year. I felt completely torn apart. I trusted him with my love, my life, our home, our finances."

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When we think about infidelity, we tend to think of the obvious. That’s sex outside of a marriage or a committed relationship, flirtations that went a step too far behind your spouse’s back, and purposely having your boundaries crossed by a partner.

What is financial infidelity?

Put simply, financial infidelity is a term describing a situation when couples with combined finances lie to each other about money. It’s the purposeful concealing of information about money that would directly affect a partner, choosing not to tell them something that they need to know.

This can include, but isn’t limited to, things like hiding missed rent, mortgage or utility bill payments from a partner when you’re the only person with access to manage the accounts, hiding financial losses like pay cuts or gambling losses.

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As many as one in three couples deal with financial infidelity in the U.S. alone, according to a Jan. 2022 survey by U.S. News and World Report. Other surveys suggest the practice is getting more common with each passing year.

Research from wealth and retirement solutions provider Aviva also shows that 38 percent of people in a relationship have a secret bank account that their partner doesn’t know about.

"In some cases it may be an attempt to feel autonomous, in others it may be a way of trying to avoid conflict."

Fe Robinson, psychotherapist and spokesperson for the UK Council for Psychotherapy (UKCP), says there are varied reasons people may conceal financial information from their partner. "In some cases it may be an attempt to feel autonomous, in others it may be a way of trying to avoid conflict," she says.

"Shame may be another component, if a person has spent money in a way they are ashamed of they may hide it to avoid further compounding their shame. The trouble is, by doing so, most often they make the whole situation worse."

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Because most people who commit financial infidelity know they are acting out a betrayal, and discussion of money is so shrouded in shame in society, the prevalence of financial infidelity often goes unnoticed, and unchecked. But the effects of financial infidelity can be astronomical.

What effect can financial infidelity have on a relationship?

Like any infidelity, financial infidelity is an abuse of trust and that loss of trust causes a lot of tension in a relationship, sometimes ending it. A 2018 study showed 76 percent of married couples involved in financial infidelity say the experience negatively impacted their relationship, and 10 percent got divorced over it.

Robinson explains that when someone is not being honest about their finances there is likely to be tension when money is discussed, often in the form of evasion, defensiveness or aggression. "It can also add financial uncertainty and strain to a relationship and living situation, affecting everyone’s wellbeing and health."

It might seem smart to keep some finances independent from a spouse, but those desires should be communicated clearly in any safe relationship. Of course, in relationships where domestic abuse is occurring, it can be a good idea to privately save money as a means to escape.

But in happy relationships where a partner believes you share your finances and this is not the case, and hiding, lying and breaking trust is involved in secret "squirrelling" of money, the effects can be devastating.

Of course, if you’re married or cohabiting, financial infidelity can have significant financial effects too. Keeping information about funds from a spouse can result in them falling into debt, having to help repay your debts, or even losing their home in cases where arrears are kept quiet.

Can a relationship survive financial infidelity?

26-year-old agriculture student Graham* says his fiancée committed financial infidelity in their relationship, and it’s something they’re working towards fixing in their relationship. "We’ve been together for five years and I never expected she would lie to me about something so serious," he tells Mashable.

"We’ve been together for five years and I never expected she would lie to me about something so serious."

Graham says his fiancée needed her car to be fixed, and "made a song and dance of pleading poverty" so he paid a few thousand for her car to be fixed.

"Months later I saw on her Monzo account when she was using her phone next to me that she had thousands in savings — more than I’ve ever had — and she’s never mentioned it," he continues. "I knew she couldn’t have saved it since, and realised she must have always had it, but she never brought it up. I felt played."

Robinson says that it can be very difficult for couples to work through financial infidelity and stay together, though it is possible. "[Mending the relationship] involves full disclosure on both parts, an open discussion about how each person is impacted by what happened, and a strong commitment to staying together," she explains.

Whether a couple intends to stay together or not, she notes that relationship counselling or therapy can be very helpful so the couple can "work through what has happened, how it came to happen, and how a couple wants to go forwards, either together or separately."

What should I do if my partner has committed financial infidelity?

For those on the receiving end of financial infidelity, finding this out and the fallout that ensues can be incredibly stressful, upsetting, and heartbreaking.

When finding something out like this that shocks and betrays us, it is hard to make good balanced decisions about what we want. For this reason, Robinson recommends anyone affected by financial infidelity make time and space to process what has happened, both practically and emotionally.

"You are likely to have many questions that need answering to understand the full situation. The best way to get this information is to find ways to calmly discuss events [with your partner] and work through them," she says. It may be that support is needed for a couple to enable these discussions comfortably, which can be found in a trusted loved one, or a relationship therapist.

As for those doing the secret stashing, anyone keeping financial information away from their life partners should find a way to be honest about what has happened, and work with their partner to decide on a way forward. Ideally, this should happen before they find out, as the secretive nature of financial infidelity, and the lies involved, are often more upsetting than the misuse of funds themselves. As Robinson says, "The longer financial infidelity goes on for the broader and deeper its impacts, it’s always best to face up to the difficulties as soon as possible."

If you experience gambling problems, call the 24/7 National Problem Gambling Helpline at 1-800-522-4700 for free, confidential support. You can also access the National Council on Problem Gambling's website for more help and information, as well as a list of international resources.