One out of every five Canadians in marriages or common law relationships confessed their significant other does not know how much debt they are in, according to a new survey by Manulife.

More than one out of every nine people admitted to having hidden the price of a large purchase from a loved one.

The insurance and financial services provider commissioned polling firm Ipsos in May to survey 2,003 Canadians on their views on money and how they impact their relationships. Because the survey was done online and therefore not randomized, it can't be assigned a margin of error, like other polls have.

One of the biggest takeaways from the findings is that one-third of respondents said finances are the major stress on their relationship, and 20 per cent went as far as admitting their partner had no idea how much debt they were in.

While a majority of couples surveyed say they regularly talk about money with a spouse, about half of them admitted that it leads to added stress. And the younger the couple, the more the stress: 43 per cent of those 35 and under said money was a source of stress. That ratio dropped to 31 per cent for those aged 35- to 54, and to 21 per cent for those 55 and over.

"Conversations around money and debt can be one of the most difficult things couples ever discuss," said Manulife Bank CEO Rick Lunny. "The trick is to get these issues out in the open and having an open and frank discussion about them."

Many survey respondents admitted they weren't following that advice. More than one-quarter of respondents said they have either hidden a purchase from their spouse or lied about how much it cost.

Most secret purchases were relatively small, with more than one-third worth less than $500. Another quarter were up to $1,000. But eight per cent of the men polled admitted they had hidden a purchase worth $15,000 or more.

Certified financial planner Shannon Lee Simmons, who had no role in conducting the survey, said the results are very much in line with her clients' experiences.

"Eighty per cent of my job is life-coaching," she said of working with couples with financial problems. "And 20 per cent is spreadsheets."

One of the biggest pitfalls that many couples make, Simmons said, is that even when they are trying to divide expenses equitably, they make the mistake of letting one partner handle fixed expenses (such as a mortgage or rent) while the other — typically the one with less income — handles fluctuating bills, such as groceries.

"That person is at a disadvantage, because they often don't know what their month is going to cost them," Simmons said. "They feel more out of control."

While so-called secret spending is indeed a problem, Simmons said the root cause of hiding the cost of purchases is usually fear, shame and guilt. From her perspective, the cure for all three is often the same thing: Communication.

And the earlier it starts, the better.

"You don't need to take out the credit report on the first date," she said. "But you definitely need to make sure everybody is getting financially naked together. … Because eventually it will come out."