A new survey has revealed that almost half of all couples couldn't be certain how much their partner earns. And while it can be a difficult thing to bring up in any relationship - especially when you have sneaking suspicion that one of you earns substantially more than the other - there are five serious risks that can arise if you're not completely clear with each other.
And some of them could leave you in serious financial trouble.
The survey, by Stowe Family Law, found that overall only 42% knew exactly what their other half was earning, 19% had a rough idea, 12% were prepared to guess, 21% had a partner who didn't earn anything, and the rest had absolutely no idea at all.
Women were more likely to have asked the question. The survey found that 43% of women know exactly what their partner earns - to the penny - compared to just 40% of men. Around the country those in Belfast were most likely to be in the dark, while those in Cardiff and Edinburgh were more likely to be in the picture.
Some 6% of people were absolutely clueless as to what their partner earns - which can open them up to five key risks
1. DisagreementsAt the most benign end of the spectrum, unless you're sure what your other half earns, there's no way to fairly divide your expenses. You'll end up rowing over every bill that comes in, or constantly feeling that one of you is being ripped off.
If you both know what the other one earns, you can have a sensible conversation about what you contribute to the boring bills, what you save for the future, and what you have left to spend on yourself.
Unfortunately having the sensible conversation won't rule out disagreements entirely (because nobody really wants to spend any of their income on the boring bills) but they will make them less of a racing certainty.
2. DeceptionFurther towards the more worrying end of the scale, if you don't know what your other half is earning, it makes it easier for them to hide things from you.
A recent survey by Forbes found that one in three people lied to their partner about bills and spending. It also found that 40% of people lost faith in a partner after discovering financial deception, 11% said it led to a separation, and 16% said it even caused a divorce.
Of course, there are plenty of little white lies about the cost of a pair of shoes, or just how much the satellite sports package costs, which aren't dreadful in the grand scheme of things. However, if your other half is overspending wildly, not paying bills, or not telling you about loans, you could end up with a serious problem.
3. OverspendingMarilyn Stowe, the Senior Partner at Stowe Family Law said: "We see many clients who either have no idea at all what their partner earns, or have completely over estimated their partner's salary."
The risk here is that rather than drawing up a budget for what you have coming into the household and what you have going out, people assume that their partner must be able to afford what they're spending. It's only when that partner has run up major debts that they realise they were overestimating their assets as a couple.
It's essential to talk about budgets - and what you will both contribute to shared costs - as well as gaining an understanding of when your other half is spending beyond their means.
4. Failure to saveIf you're not talking about money, there's every chance you have no idea if your partner is saving for emergencies, investing for the medium term, or building up a pension.
If you're both taking separate precautions, then there may be no harm done, but if you are both simply assuming that the other person will be able to deal with it on your behalf, then the next time the car breaks down, you want to take a holiday, or the day before you retire, you could be in for a horrible shock.
5. Major loss if things go wrongOf course no-one wants to think of what would happen in the event of a divorce, but there are a huge number of cases which come to court where one part of the couple has no idea what the other half owns or earns - making it easier for them to hide their true worth and negotiate an unfair settlement.
Stowe warns: "When a relationship has come to an end the greater the financial transparency there is between the couple the less stressful the divorce proceedings will be."