Have you committed financial infidelity?

What’s mine is yours – so goes the old adage. Many couples, however, are using their own loose interpretation of this loving declaration: either freely spending their partner’s money without their knowledge or keeping a tidy sum to themselves.

And this is more common than you think. According to a study by AXA, as many as one in three people admit to having misled their partner about the state of their finances.

It is easy to tell ourselves that hiding some of our financial indiscretions from our partner isn’t a big deal, but something that starts out as a small financial fib or white lie could escalate into something much more serious. You could find yourself in the habit of lying to your partner regularly – not because you set out to deceive them but because you are embarrassed about how you handle your money.

“Lying about our finances is a sign that we are worried about being criticised and, in some cases, ejected from the relationship,” explains psychologist Philip Hodson.

But this could have dire consequences, warns Tom Howard, spokesperson for Consumer Credit Counselling Services, a charity. “The more serious financial lies can be incredibly damaging and jeopardising. If you have a house with a mortgage and are consistently spending on credit but not telling your partner, this could affect mortgage repayments and even lead to your house being repossessed.”

Aside from affecting your monetary situation, constantly deceiving your partner can have an adverse affect on your relationship too. Hodson gives the example of one woman who divorced her husband because he was constantly relying on his overdraft and his wife couldn’t cope.

Owning up to your fiscal misdemeanours may be embarrassing but, if you are in serious debt, the emotional support that you could get from your partner is worth more than trying to preserve your pride.

But what do we lie about? Here is a list of the top 10 most common financial fibs we tell our loved ones:

1. Debt and bills

Telling your partner that the phone bill is £100 more than normal because you made one too many long-distance calls is embarrassing enough; however, many of us are hiding larger amounts of debt from our loved ones. In a survey by credit reference agency Equifax, 23% of respondents admitted keeping their debts secret; of those, 29% revealed that they were hiding debts of more than £5,000.

2. How much you’ve spent

Knocking a nought off your bar bill, saying your designer shoes were from Primark or claiming you’ve got your latest gadget in the sales – most of us think little of this type of white lie. In fact, nearly one in four women admit to telling their partners that a new purchase cost less than it really did, according to First Direct.

Philip Hodson, fellow of the British Association for Counselling and Psychotherapy, compares this to eating biscuits. “You might only eat one or two in front of other people so that you don’t look greedy; however, if you eat 18 jaffa cakes by yourself, then you don’t notice how much you’ve eaten. You just take one after another. ”

3. Hiding new purchases

If you can’t face lying to your partner about the cost of something, you might hide it for a few months until any suspicion has subsided – or the credit card bill has been paid off. This has become easy to do because many of us order our purchases online or over the phone, meaning they can be delivered to a work address and your partner at home will be none the wiser.

On AXA’s confessional website, mybudgetday.axa.co.uk, which lets users post their money lies, one user admits: “When I buy new shoes or clothes, I hide them in the back of my wardrobe and tell my partner they are old.” Another 2,183 people admitted to doing this, making it the fifth most common lie on the website.

4. Secret bank accounts

While family finances used to be kept together, these days many couples have their own bank accounts and keep their finances separate. Only 8% of co-habiting couples have joint accounts although the number goes up to 44% for married couples, according to research by Alliance & Leicester.

While there’s nothing wrong with keeping your finances separate, some people go as far as setting up a bank account which their partner knows nothing about. There are websites for those who wish to hide the amount of money they have, with some advising well-off spouses on how to hide their fortunes, while others recommend that you should always have a secret ‘runaway fund’ in case of a break-up.

5. Inherited money

With fewer people holding joint accounts, the £100,000 windfall that Auntie Aggie left you can remain a secret from your partner. They won’t see it on the bank statement and you have the freedom to make lavish purchases because the money hasn’t been earmarked for the car repayments.

AXA’s online confessional has a fair few people admitting to hiding inherited money, with one user defending her deception by claiming her husband would blow the money if he knew about it. “My parents have given me over £3,000 but I’m not telling my husband as he’ll just spend it.”

6. Losing your job

At the beginning of the film The Full Monty, actor Tom Wilkinson cuts a lonely figure as a redundant ex–foreman. His character, Gerald Arthur Cooper, is so ashamed he has lost his job that he doesn’t tell his wife he is going to the job centre every day. Instead he leaves the house each morning in a suit and tie with the sandwiches his wife makes for him.

It can be difficult to admit you’ve lost your job. With redundancies on the up, this is likely to become more common.

7. Keeping quiet about salary or other incomes

Your salary is a sensitive point. Some people are embarrassed about how little they earn, while others don’t want to reveal just how well off they really are. This is mirrored by a survey by Ceridian, a human resource services provider, which showed that 53% of Brits don’t share their salary details with their families.

Aside from keeping quiet about their basic pay packet, partners are lying about bonuses and pay rises. Some take a step even further. Heidi Evans’ book How to Hide Money From Your Husband: And Other Time–Honoured Ways To Build A Nest Egg suggests getting a secret part–time job so that the second salary doesn’t have to be shared.

8. Money lost or money won

Bookmakers William Hill, Paddy Power and Ladbrokes have all seen revenues increase thanks to punters trying to glean some light relief and happiness amidst the recession. However, with less money to waste, money on the horses might be a luxury you’ve jointly agreed you can’t afford.

So, if your partner only ever seems to win, chances are they aren’t telling you about their losses. A former gambler explains how easy it is to rack up debts: “I racked up a huge amount of debt on loans, overdrafts and credit cards. I eventually sought professional help and I am making huge steps to improving my financial situation.”

9. Pocketing the change

It is easy for your partner to say the £80 weekly shopping bill cost £100 and pocket the difference. They could be squirreling away this extra money for a treat for both of you. There is the chance, though, that the £20 is going on things you’ll never see, from your husband’s beer money to your wife’s make-up fund – delete as appropriate.

10. Hiding credit card statements and bills

One fifth of women admit to destroying receipts and statements after going shopping, according to research by First Direct. Male partners may have no idea how much their spouses spend on new shoes and they also have no way of knowing how many pairs of shoes were bought on credit.