They say keeping secrets can kill a relationship but it can also present a difficult dilemma when it comes to talking about money and how much you earn.
The odds of two people in a relationship earning the same are virtually non-existent - a problem which means there is always potential for jealousy to arise.
But, says Tom Hartmann - managing editor of Sorted - the government's money education website, if couples don't talk about how much they earn it can stop them from reaching common goals.
New research released by the Commission for Financial Capability as part of Money Week has revealed more than half of couples don't talk about how much they earn and it is higher still for younger generations.
"There has always been barriers to sharing how much you earn even at home. As soon as it comes out in the open people start comparing."
Hartmann said people feared that would create jealousy and pressure on the higher earner to give money to the lower earner.
But he says we should talk to our partners about it.
"We should talk to our partner about a lot of things and that is just one component because in a partnership we can achieve more by working together."
He urges couples to skip judgement about the other person's spending decisions and think about how they feel about money - a sense which is often guided by how someone is brought up to think about money.
Money is often a point of contention and can lead to arguments.
But Hartmann says often money arguments are really about something else.
"They are about control or past things that may not have gone as well as they should have."
Couples are also far more likely to talk about bills than debts they have. Two-thirds of people said they had had a conversation with their partner about bills but just over a quarter (26 per cent) had talked about personal loans.
"The other things we are hiding is spending, it's not just about income. There are these sensitivities around the choices we make."
Hartmann says what we spend money on can show what people believe is important and how we pay for that can impact our partner whether we share the information or not.
One example of that is a poor credit history for one partner stopping a couple from taking other loans like a mortgage.
Hartmann says keeping money separate and not sharing information is an increasing trend which is coming with societal change.
"Part of it is society. People are more and more likely to be living on their own. They might have a partner but are not living together so they are not joining up their finances as much as people used to.
"Society has become much more individualistic."
The research found just 38 per cent of people talked about planning for retirement and even for those in the 55 to 64 age group just over half discussed it with their partner.
But Hartmann said retirement was something that needed to be planned together.
The theme of this year's Money Week, Now We're Talking, aims to encourage New Zealanders to open up and start those tricky conversations.
"Not talking about money can be a source of stress, anxiety and unnecessary problems for many people," says Hartmann.
"Personal finances are intertwined with our relationships – how we handle money affects those around us, and vice versa."