We all have secrets. Maybe you've sneakily watched the next episode of White Lotus without your partner (when you swore you’d wait), or quietly finished the last Tim Tam and blamed the dog. Harmless? Mostly. But not all secrets are created equal – especially when they mess with trust and money.

So… what exactly is financial infidelity?

Think of it as cheating, but with your bank account. It's when someone in a relationship hides, lies about, or secretly makes decisions around money that break the trust of their partner.

Like other forms of infidelity, it has two key ingredients:

1. Crossing a boundary (you know, the unspoken agreement not to blow $3K on crypto without mentioning it).
2. Hiding it, lying or omitting the truth to cover it up.

What does financial cheating actually look like?

It’s not always dramatic, but it’s often sneaky:

• Hiding credit card debt or maxing out buy-now-pay-later accounts
• Keeping a secret savings stash (or a secret splurge fund)
• Lying about income or bonuses
• Gambling in secret
• Making major financial decisions solo when it’s supposed to be a team effort

It’s the financial equivalent of texting your ex behind your partner’s back.

How common is it?

You might be surprised, in a recent Compare the Market survey of over 1,000 Australians, 1 in 5 Australians admitted to financial cheating. Of these people:

• ~32% lied about what they spent their money on
• ~25% lied about how much debt they were in
• ~22% lied about their income
• ~13% lied about how much they spent on gambling

A Finder survey of over 1,000 Australians revealed that 1 in 5 people thought financial cheating was worse than physically cheating. 

Finance expert Sarah Megginson from Finder puts it simply: “Financial lies can be quite destructive and leave people feeling betrayed and untrusting”, especially when the couple share finances. 

Why do people financially cheat, and what does it do to a relationship?

Let’s be real, money can be a pretty awkward topic for couples to talk about. It’s right up there with exes, in-laws, and politics. So it’s no wonder financial infidelity happens more often than we’d like to admit.

People keep money secrets for all sorts of reasons:

• Embarrassment or shame – maybe they’ve racked up a bit of debt or splurged on something they regret (looking at you, impulse Dyson Airwrap purchase).
• Fear of judgment – especially if one partner is more “saver” and the other is a “spender.”
• Compulsive behaviour – like a shopping addiction or sports bets that keep racking up.
• Conflict avoidance – they’d rather hide it than have another tense conversation about finances.
• Or sometimes, it’s the thrill of secrecy — that little adrenaline buzz from “getting away with it.”

And lately? It’s been even harder.

With soaring rent, grocery bills that feel like a straight up scam, and petrol prices that just never went down - a lot of Aussies are feeling the financial squeeze. In this climate, some people might convince themselves that they’re protecting their partner by keeping things under wraps.

But as financial educator Melissa Browne points out, “so many people are financially stressed with the rising cost of living and interest rates, so to have their partner do something that threatens that financial safety could feel like an enormous betrayal.”

Stay tuned for Part 2, where we cover how to avoid the financial infidelity trap, and what to do if you find yourself in this sticky situation.