What is financial infidelity?
Financial infidelity is engaging in a financial behavior you expect your partner to disapprove of, and intentionally not telling them about it. That definition comes from a 2020 paper in the Journal of Consumer Research by Emily Garbinsky, Joe Gladstone, Hristina Nikolova, and Jenny Olson — the first research team to define and measure the behavior rather than just poll about it.
The definition has two parts, and both matter. There has to be an act you expect would elicit disapproval, and there has to be concealment — an intentional failure to disclose it. Hiding a surprise birthday gift isn’t financial infidelity: there’s concealment, but no expected disapproval. Spending freely from a shared account in full view isn’t either: your partner may disapprove, but nothing is hidden. The betrayal lives specifically in the overlap — doing the thing and burying it.
Americans take that overlap seriously. In a Bankrate survey of 2,564 U.S. adults fielded in December 2025, 43% said keeping financial secrets from a partner is at least as bad as physical infidelity — 38% called it equally bad, and 5% called it worse.
Sources: Garbinsky, Gladstone, Nikolova & Olson, Journal of Consumer Research, 2020; Bankrate Financial Infidelity Survey, 2026
What counts as hiding money?
Before writing their scale, the researchers asked married adults to describe behaviors they would consider financial infidelity in their own marriage. From 699 participant-generated examples, they distilled 12 categories. Most of them fall into four recognizable families:
Hidden spending
Purchases your partner never sees — including lying about what something cost, or quietly spending money the two of you had saved.
Secret accounts
A bank account, credit card, or stash of cash your partner doesn’t know exists — or one they know about but can’t see into.
Undisclosed debt
Balances that grow in the dark: credit cards, loans, unpaid bills your partner believes are handled.
Misstated income
Lying about how much you earn, where it comes from, or the raise and side income that never made it into the family math.
The remaining categories run darker — undisclosed gambling, hidden investments, giving money away without agreement, even deliberately harming a spouse financially. What unites all 12 is not the dollar amount. The researchers note that what counts as trivial for one couple is substantial for another; it’s the expectation of disapproval plus the cover-up that defines the act.
Source: Garbinsky, Gladstone, Nikolova & Olson, Journal of Consumer Research, 2020
How common is financial infidelity?
Among adults who have ever combined finances with a partner, roughly four in ten report being on the receiving end of a money deception. A National Endowment for Financial Education poll conducted by The Harris Poll in June 2021 asked 2,073 U.S. adults about deception in relationships where finances were combined:
Men confessed more often than women — 47% versus 39%. And about one in five (21%) admitted to outright lying about finances, the amount of debt they owed, or how much they earned.
The Bankrate survey measures something adjacent — not deception itself, but the absence of full visibility: 45% of Americans in committed relationships say they and their partner do not know everything about each other’s finances. Some of that gap is agreed-on privacy rather than concealment. And among Americans in committed relationships, 25% are currently keeping minor sources of debt, expenses, or income secret from their partner — while 9% are keeping major ones.
Two 43s, two different facts. By coincidence, both headline numbers are 43%. Bankrate’s 43% measures a belief — U.S. adults who say financial secrets are at least as bad as cheating. NEFE’s 43% measures a behavior — adults who ever combined finances and admit to at least one act NEFE classes as financial deception, from hiding a purchase to lying about debt. The number repeats; the denominator doesn’t. Bankrate asked 2,564 U.S. adults; NEFE’s 43% comes from the 1,248 respondents who said they had ever combined finances with a partner.
Sources: NEFE / The Harris Poll, 2021; Bankrate Financial Infidelity Survey, 2026
Why do partners hide money?
When NEFE asked the 555 respondents who admitted a financial deception why they did it, the answers looked less like villainy and more like avoidance — every figure below is a share of that group, not of all adults:
- 38% believe some aspects of their finances should stay private
- 34% feared disapproval from a partner — in relationships where money talks had already happened
- 33% were embarrassed or fearful about their finances and didn’t want their partner to know
- 27% feared disapproval in relationships where finances hadn’t been discussed yet
Notice what tops the list. It isn’t malice — it’s a privacy claim, and a sizeable minority of partnered adults hold it openly: in Bankrate’s survey, 28% of those withholding financial information say the main reason is that they should be allowed to keep some things to themselves.
Notice the second reason, too. Read it carefully: both fear-of-disapproval figures come from the same group — people who had already hidden something — so they rank motives rather than measure who hides more. Within that group, though, the more commonly cited fear was disapproval in a relationship where the money conversation had already happened (34%), ahead of fear in one where it hadn’t (27%). Talking is where most couples already struggle — and at minimum, these answers say a prior money talk doesn’t take concealment off the table.
Sources: NEFE / The Harris Poll, 2021; Bankrate, 2026
The secret taxes the keeper, too
The partner being deceived isn’t the only one paying. A 2017 paper in the Journal of Personality and Social Psychology by Michael Slepian, Jinseok Chun, and Malia Mason analyzed more than 13,000 secrets across their participant samples and found that what predicts the burden of a secret isn’t mainly the lying — it’s the carrying.
People rarely face moments that force active concealment; the conversation where you must steer around the hidden credit card comes up occasionally. But your own mind brings the secret back more often than any conversation does. In their studies, participants’ minds wandered to their secrets 2.44 and 1.84 times more often than they had to actively conceal them in conversation. And it was the mind-wandering — not the concealing — that predicted lower well-being.
A hidden account is a permanent resident of exactly this kind. It doesn’t come up once; it hums in the background of every statement cycle, every shared purchase, every casual “should we book the trip?” If money secrets behave like the secrets in these studies — which pooled 38 categories, financial and otherwise — the keeper keeps paying that tax, in a currency no statement itemizes.
Source: Slepian, Chun & Mason, Journal of Personality and Social Psychology, 2017
What financial infidelity does to a relationship
When the deception surfaces — and statements, credit checks, and mail have a way of surfacing it — the people who lived it describe real damage. Among the 650 NEFE respondents who combined finances and were on either side of a deception, 85% said it affected the relationship. The outcomes they attribute to it:
One caveat on the last card: NEFE notes that respondents who are currently single and never married were not offered the separation, divorce, or proactive-communication answers at all, so those options rest on a narrower base than the rest.
“Regardless of the severity of the act, financial infidelity can cause tremendous strain on couples — it leads to arguments, a breakdown of trust, and in some cases, separation or even divorce.”
— Billy Hensley, president and CEO, National Endowment for Financial Education
Honesty about the data cuts both ways: 19% of respondents said the deception ultimately brought the couple closer, and 16% said it pushed them to communicate proactively. In those couples’ telling, the surfacing was the turning point. But that’s a bet on the crash landing going well — and the most commonly reported outcome is the argument, not the breakthrough.
Source: NEFE / The Harris Poll, 2021
What a default setting reveals about hiding
The most interesting evidence in the Garbinsky paper isn’t a survey answer. It’s what people did inside a real couples’ money-management app. The research team paired survey responses with the app’s actual settings data for 1,169 users holding 9,010 linked accounts, and looked at one specific choice: account visibility.
For every account a user chose to connect, the app’s default visibility setting shared everything — balances and transactions both visible to the partner. Hiding an account, or showing the balance while hiding the transactions, requires actively changing a setting. The researchers conceptualized those opt-outs as the concealment half of financial infidelity — the settings data can’t show whether a hidden account funded anything a partner would actually disapprove of, only that it was deliberately hidden — and found that people who scored higher on their financial-infidelity scale were significantly more likely to have flipped one.
Why the default matters: the study is correlational — no one has randomized couples into transparent defaults and measured what happens to secrecy. But the architecture it observed is instructive: when transparency is the default, secrecy requires a deliberate act — one that a scale measuring the tendency to hide can actually predict. Flip the architecture and the logic flips with it: where money is opaque by default, honesty becomes the thing requiring repeated effort — disclosure conversation by disclosure conversation, statement by statement. Couples don’t drift into transparency. They build it, or default into its opposite.
This is the practical insight the surveys can’t give you. Self-reports capture what people say about money; this data captured what they did with a setting — and the tendency to hide showed up as a deliberate opt-out from a transparent default. No study has yet tested the intervention, but the bet it points to is structure over resolutions: a couple that sets up systems where shared money is visible by default isn’t relying on a daily choice to disclose — where such a default existed, hiding had to announce itself as a choice.
Source: Garbinsky, Gladstone, Nikolova & Olson, Journal of Consumer Research, 2020
Privacy or infidelity? Where the line actually sits
None of this research says partners must surrender all financial autonomy. Remember the top reason the people who admitted a deception gave for it: the belief that some finances should stay private. The definition itself draws the usable line. Financial infidelity requires expected disapproval plus concealment — which means anything your partner has genuinely agreed doesn’t need disclosing isn’t infidelity. It’s privacy, operating inside the rules.
That turns an abstract virtue — “be transparent” — into three concrete agreements a couple can make once, instead of a negotiation they must re-run forever:
Agree on the private zone. A personal allowance each partner spends with no questions asked converts secret spending into sanctioned spending. The act is identical; the concealment — and the expected disapproval — are gone.
Agree on a disclosure threshold. Many couples use a simple rule: purchases over a set amount get mentioned before or after. The number matters less than its existence — it defines, in advance, what “hiding” means. (The shared layer itself is real money: across splitty’s US-leaning receipts, nearly half — 48% — of restaurant bills, as whole-table totals, come to $150 or more.)
Make the shared layer visible by default. Whatever you both pay into — rent, dinners out, trips, the joint card — should be structurally visible to both of you, so honesty about shared money never depends on anyone’s memory or courage.
Couples deciding how to organize the whole system — one pot, two pots, or a hybrid — are making a different decision, with its own research on which structures correlate with staying together. The line drawn here is narrower and comes first: whatever the system, the shared parts shouldn’t have dark corners.
Source: splitty first-party receipt data, 2026-09-02 snapshot — US-leaning receipts scanned in splitty, not a national sample
Start with the money you spend together
You can’t make a partner’s private accounts transparent — that’s theirs to offer. What a couple can control tonight is the shared layer: the dinners, the groceries, the weekend trip with friends where one of you fronts the bill. This is where hidden money math can start small — the restaurant total quietly rounded up, the split nobody wants to relitigate, the “I’ll just cover it” that becomes a number nobody wrote down.
splitty’s job is that layer. Scan the itemized receipt and the split is laid out line by line: each item, who shared it, what each person’s share of tax and tip comes to. Each person gets a pre-filled payment request for exactly their share, and a Share Split link opens the same itemized breakdown on the web for anyone who wants to check it — no app, no account. No spreadsheet kept by one person, no math performed behind anyone’s back — the bill itself becomes the shared record, disclosed by default.
To be precise about scope: splitty settles tonight’s bill; it isn’t a couples’ ledger and doesn’t monitor anyone’s accounts. The deeper architecture — whose accounts are visible, what gets pooled — is the couple’s to design. But transparency is a habit with a smallest unit, and the smallest unit is the bill in front of you. Split it in the open, every time, and “we can see our shared money” stops being a resolution. It’s just how you already do it.
