If one person in the relationship loses or spends a lot of money they may be afraid to tell the other person because they don't want to disappoint them. Photo / Thinkstock
When former Oasis front-man Noel Gallagher lost millions of dollars trying to set up his solo music career it took him a whole year to tell his wife.
Most of us don't have that kind of money to lose or spend but the angst of telling the other half can be just as difficult.
Clinical psychologist and senior lecturer at AUT University, Mark Thorpe, says there is no cook-book recipe as to why some people lie or try to hide their spending because it comes down to what money means to that person and what it represents in the relationship.
Thorpe said many people had a strong connection between love and money. But for others it also represented care, security, safety or dependence.
If one person in the relationship loses or spends a lot of money they may be afraid to tell the other person because they don't want to disappoint them, Thorpe said.
For a traditional man losing his job and income can mean he no longer feels important and may feel looked down upon.
Or it may be that one person in the relationship feels dependent on the other for money and that makes them unhappy so they respond by having a big spend up.
"It may be sparked by some underlying reason."
If it has never happened before Thorpe says it pays to ask why now?
Many of the couples Thorpe sees keep their money separate but he doesn't believe it is that common in the general population.
Thorpe said sharing finances was a position of trust - not sharing meant something had gone awry.
"It takes a certain level of commitment in a relationship before they start having joint accounts. It's not about how long a couple have been together but the commitment they have to each other."
But financial adviser Liz Koh says keeping separate accounts can be sub-optimal especially when it comes to achieving long term goals.
She believes it's far better to combine incomes into one account and then dole out an agreed amount of "pocket money."
If couples have an agreed amount of money they get to spend then they don't have to be answerable to the other person. That takes away the friction.
"It's about being proactive.
"If couples have an agreed amount of money they get to spend then they don't have to be answerable to the other person. That takes away the friction," says Koh.
She believes the main reason people hide things is because they feel guilty.
Koh doesn't come across many couples who lie about their spending but more commonly sees a situation where one person in the relationship spends money on things which the other person does not believe is appropriate.
That could be a hobby, expensive shoes or dresses or technology.
"One person may believe the money could be better spent on other things. It is less common for people to hide their spending - but I'm sure it does happen."
She advocates sharing financial information.
"Couples that are open and transparent can't hide anything from their other half."
When it comes to investing women can tend to take the back seat leaving it up to the men to be entrepreneurs.
But Koh says if you are in a relationship you need to understand what you are agreeing to.
"If you allow yourself to take a back seat you have got to accept the circumstances."
Koh reckons both parties should take responsibility and get involved and if you don't have the knowledge to understand what is going on, go get it.
Tips for money talk
* Talk about the relationship and where it is at present as openly as possible and how that relates to money - who earns what and what accounts are held, what are the joint family goals.
* If one person has a big spend-up it may have something to do with what is going on in their life or how they are feeling towards their partner. Ask why now and what is causing the underlying feeling.
* Be open and transparent.
* Have an agreed amount of "pocket money" which you can spend on anything you want to spend it on.
* If you don't understand what is happening to your finances get help.