Seven Financial Secrets Your Spouse May Be Keeping From You

Plus, a bonus eight steps you can take to ensure you’re financially aligned with each other

We build our lives on trust.

We trust our colleagues, our friends, our family, teammates, and of course our spouse.

We trust our partner to be faithful, to be honest about their day, and to tell us if we have spinach in our teeth. Yet, when it comes to money, a surprising number of people (even those in long-term, loving relationships) turn into world-class spies. They are committing what some psychologists call financial infidelity.

Financial infidelity is defined as financially deceiving a romantic partner, a calculated breach of trust that can range from minor hidden purchases to concealed six-figure debts. Just like sexual or emotional cheating, financial infidelity can destroy relationships. For many, discovering a financial secret feels just as devastating as romantic betrayal. Why? Because money is fundamentally tied to our future, our perception or lack of safety, and our core values. A secret about a credit card is rarely just about the credit card; it is a symptom of a deeper fracture in the foundation of transparency.

When someone hides money matters from the person they love, it is rarely only about dollars. It often signals stress, fear, shame, or power struggles bubbling beneath the surface.

What Are New Zealand’s Worst Relationship Financial Secrets?

Financial secrecy is more common than many Kiwis expect. A recent surveys show that roughly a quarter of New Zealanders in serious relationships keep financial secrets, including hidden debts, private accounts, or undisclosed spending. These are close cousins to financial infidelity, a pattern psychologists identify as one of the strongest predictors of relationship tension and emotional withdrawal.

Another older survey indicated nearly 18% of Kiwis had hidden money or debt their partner was unaware of.

Across the ditch, the numbers echo these figures, with over a quarter of Australians reporting a financial activity hidden from their better halves. The data confirms financial deception is not an isolated problem; it is a common challenge for countless couples navigating modern financial pressures.

Unsurprisingly, research published in the Journal of Consumer Research has found that financial infidelity has a profound negative effect on relationship satisfaction. Financial deception doesn’t just drain bank accounts; it erodes the fundamental trust required for a life partnership.

Before going further, it is important to say this: money secrecy does not automatically equal malice.

• Humans are complex. Sometimes the “secret” is a new pair of shoes purchased during a weak moment. Sometimes it is a hidden credit card. Sometimes it is someone pretending the $400 they spent on fishing gear was “on sale” when it was not!
• The nature of a typical Kiwi family has changed over time. A heterosexual married couple and two or three children is no longer the norm. When it comes to money, blended families can add another dimension, and unique financial disclosure challenges. When children from previous relationships, child support arrangements, or shared caregiving obligations are involved, money conversations can feel more sensitive. People sometimes withhold details to avoid conflict with ex-partners, protect children, or prevent tension between new and existing family members. Financial boundaries can also be unclear, not because people are deceptive, but because they are juggling multiple emotional and financial commitments and may have come into the relationship with different levels of assets and family-related expenditure. Open communication becomes even more crucial in these situations, helping partners build trust.

With that in mind, here are seven financial secrets a spouse might keep, grounded in recent research, and how they connect to deeper relationship patterns. Also, read on to learn how to avoid these issues.

1. Secret Purchases and Spending

This is the most frequent form of financial infidelity. It starts innocently enough. A new pair of shoes tucked into the back of the wardrobe, a tool bought and claimed as "old." But it can escalate to major purchases kept entirely off the books, like an expensive appliance, electronics, or even a vehicle.

ASB found that the most common secret kept by New Zealand couples is hiding spending or purchases. Australian data reinforces this, noting that seven percent of people have secretly made a significant purchase, such as a car or luxury item, without consulting their partner.

What it reflects: A fear of confrontation or judgment. The secret-keeper anticipates disapproval and chooses avoidance over open communication, valuing (possibly short-term) momentary gratification over shared accountability.

2. The Hidden Hoard: Undisclosed Assets

Financial infidelity is not always about hiding bad habits or debt.

Sometimes it is about hiding assets, savings, or even new investments. This often takes the form of a secret bank account or a 'slush fund' the other partner knows nothing about.

In the most recent Australian data, one in four reported hiding money from their partners!

In New Zealand, the majority of people who kept secrets, 67.3%, were hiding private bank accounts or cash reserves. The motivation here can be complex.

What it reflects: A desire for power and independence. While striving for financial independence is positive, keeping an entire cache of money secret is often about protecting oneself in case of a breakup or maintaining a power imbalance. It signals a fundamental lack of commitment to the shared future. The person is mentally planning for an "exit" or ensuring they have ultimate control over at least some of the couple's resources.

Learn more: Financial red flags to watch for in your spouse

3. Hidden Debt

Hidden debt is arguably the most destructive secret, as its fallout can legally entangle both partners, especially in a divorce or separation. This often involves secret credit cards, personal loans, or undisclosed overdrafts.

Nearly one in ten Australians have secretly accumulated debt via a credit card or personal loan. The last time similar data was collected in New Zealand was 2017, when 18% of those keeping secrets had hidden debt. Given the economic ups and downs since then, and the re-emergence of cost-of-living pressures, we think the numbers could be higher nowadays.

Furthermore, a significant number of Kiwis, over one in four in fact, report being financially hurt by a partner, often through the partner racking up secret credit card debt.

What it reflects: Shame, a lack of control, or financial insecurity. Hidden debt is often fuelled by a profound fear of failing to meet a partner's expectations or a personal inability to manage impulse control. It might also be a sign of deeper behavioural issues.

4. Secret Gambling and Addiction

While specific data on gambling is often difficult to track, it is a well-known driver of financial secrecy. Addiction, whether to gambling, shopping, drugs, or other activities, might inevitably require hiding large, sudden losses or expenses.

Australian data provides a clear warning which is likely to be similar to New Zealand numbers: nine percent of people in relationships admitted to gambling money without their partner’s knowledge. This is often an extreme extension of the "hidden debt" secret.

What it reflects: Addiction and denial. Hiding gambling or shopping losses suggests a profound inability to manage destructive behaviours, prioritising the addiction above the security and trust of the relationship. It is a severe red flag indicating professional help is needed, not just a financial fix.

5. Silent Income: Raises, Bonuses, or Inheritances

When finances are intertwined, hiding an unexpected influx of cash is a clear act of deception. This could be a sizeable tax refund, annual bonus, a pay rise, an inheritance, or another lump sum.

New Zealand research suggested more men conceal income from their partners than women. This secret income may be used to quietly fund the hidden accounts or pay down the secret debt.

What it reflects: Greed or differing values. Hiding income suggests the person feels entitled to that money individually, often reflecting an inability to see the couple as a unified financial unit. This might be a sign of a chasm in financial vision for the future.

6. Covert Gifts

Helping family or friends financially is a kind and generous act, but when it is done in secret with joint funds, it becomes financial infidelity. This could range from large loans to relatives to becoming a guarantor on a loan without a partner's knowledge.

Australian data showed eight percent of people secretly help a family member or friend financially without disclosure.

What it reflects: A need to be a 'hero', difficulty setting boundaries, or difficulty communicating. This secret indicates the partner is unable to have tough conversations, both with their own family and with their spouse. They might value external approval or peace over their commitment to their partner’s financial security.

Related articles:

• ‍How to avoid fights over money
• Prenuptial agreements: your guide to safeguarding love and assets
• Financial red flags to watch for in your partner
• Warning signs you’re in financial danger
• The worst ways to waste money

7. Lie By Omission: Pretending Financial Ignorance

This secret is subtle but pervasive. It is not an active lie, but a sustained pattern of deliberately avoiding joint financial responsibility. When one partner handles all the bills, accounts, and investments, and the other partner remains passively ignorant, they are allowing a secret to flourish.

A ten year old New Zealand survey reported over a third (36%) of newlyweds did not know anything about their partner’s spending habits. This ignorance can be exploited by the partner in control, or it can leave the ignorant partner vulnerable if the relationship ends.

Beyond the Balance Sheet: The Roots of Financial Deception

Financial infidelity is usually a relationship problem wrapped in a financial package.

When we see a partner engaging in one of these seven secrets, it is essential to look beyond the dollar value and assess the underlying drivers. These secrets are often rooted in:

• Fear and Shame: The secret-keeper is often afraid of being judged, criticised, or viewed as a failure. This shame is powerful and can compel an otherwise honest person to lie.
• Control and Power: Money is control. By hiding accounts, assets, or racking up debt unilaterally, a person asserts their individual power over what should be a loving partnership. This imbalance is a hallmark of an unhealthy relationship dynamic.
• A Lack of Shared Vision: Financial secrets thrive when couples have not clearly defined their shared financial aims. If one partner is saving aggressively for a house and the other is secretly spending for short-term luxury, their conflicting priorities make secrecy inevitable.

If you tolerate deceit and avoidance, you will drift toward deeper relationship and financial problems. Put another way, it’s not your finances which are at risk, it’s the whole foundation of your relationship.

A Path to Financial Intimacy: Build Trust Together

If you recognise any of these secrets or underlying issues in your relationship, the news is good: you have an opportunity to strengthen your partnership. Being aware of the problem is the first and most critical step towards realignment. Focusing on building positive financial behaviours is the ultimate prevention.

1. Financial Transparency

You need to establish a full and frank disclosure. This means disclosing all income, assets, and debts. This is not out of obligation, but out of commitment.

This can become an ethical cornerstone of your relationship. When you communicate openly, you replace shame and fear with trust and support.

2. Establish a "Guilt-Free" Spending Buffer

There are several choices here:

• One common reason for hidden spending is the desire for personal autonomy. To combat this, you might agree on a personal spending limit, a specific amount each partner can spend, weekly or monthly, without consulting the other or having to justify the purchase.
• Alternatively, you might allocate set amounts to each other’s personal bank accounts which can be freely saved or spent as you please, without the need to check in with your spouse.
• Many couples share transparency rather than control. This means both can see all accounts without requiring permission to spend.

Whatever you do, this sort of practical step will reduce the need for secrecy and satisfies the natural human desire for a degree of independence, provided it is managed responsibly and within the joint budget.

3. Create a Shared Vision

Seek alignment with your hopes and dreams.

It’s a lot easier to be aligned with money if you are building a great life together and can be excited about the future.

This means you can be more focussed on what you are aiming towards, and less on boring cost-cutting! Are you working toward a family holiday, a new home, a big item such as a boat, a secure or early retirement, or something else? When you tie your money conversations to an inspiring, shared vision, the process shifts from being restrictive to being empowering. This shared purpose helps align your daily financial choices and makes it easier to keep your commitments to each other.

4. Review Your Accounts Together

Once you’ve got alignment on a great future together, this sort of conversation should be a lot easier.

Short, honest conversations remove guesswork. No lectures. No blame. A simple and regular query such as “How are we doing money wise?” might transform a relationship.

5. Stay Financially Literate

Your personal financial education is a non-negotiable part of modern adult life. Dedicating time to learning core personal financial concepts, then staying reasonably up to date in those areas, is your best bet for financial security. This literacy empowers you to participate actively in your shared financial destiny. Without it, you remain vulnerable to making poor decisions, being exploited, or failing to recognise signs of financial infidelity.

6. Work Together, Don’t Blindly Outsource Everything Financial To Your Spouse!

Never fully outsource your financial life to your spouse or partner.

While delegating tasks can be efficient, maintaining total ignorance of joint accounts, investments, and debt levels is dangerous. In the event of an unexpected crisis, such as separation, illness, or death, you must possess the knowledge to manage your assets and obligations instantly. Staying informed ensures you are an equal and informed partner who can verify decisions and maintain alignment, including alignment as you work towards your hopes and dreams.

7. Seek Guidance Together

Seeking guidance from a financial adviser, including us here at Become Wealth, can provide an impartial, broad-minded path for you to realise your financial independence as a couple. (Get in touch to learn more). This will boost your confidence, including the confidence to celebrate wins along the way. 

Alternatively, for behavioural issues, a relationship therapist can help uncover the deeper emotional triggers driving any financial deceit, or other trouble. Addressing the root cause is the only way to ensure the financial secrets do not return.

Building a life together is a continuous process of shared growth. By fostering open communication around money, you are not just safeguarding your bank balance; you are fortifying your relationship against the betrayal and mistrust that financial secrets inevitably bring.

8. Positive Reinforcement

If a partner opens up about a difficult financial issue, or a financial mistake, respond with patience rather than frustration.

This encourages honesty next time.

The Bottom Line: Money Secrets in Relationships

Ultimately, the greatest asset a couple possesses is not a KiwiSaver Scheme account balance or other number on a screen, but the integrity of their trust. Choosing financial transparency means choosing a partnership built on resilience, honesty, and shared dreams. When you commit to opening the books together, you are not just managing money; you are reinforcing your commitment to each other, creating a future that is not only wealthier but fundamentally stronger. Your greatest wealth is your unity.

If you and your partner are ready to have an honest conversation about your financial future and ensure your goals are aligned, book a complimentary initial consultation with the team here at Become Wealth. We’ll help you continue your journey toward financial intimacy.