Are you hiding money from your live-in partner?

Money guide for Millennials
Money guide for Millennials

It's not a good look to be stupid about money. But it can be a deal-breaker to be dishonest about it, especially when it comes to partners in love.

As it turns out, this is the person who is also your partner in money.

Some 15 million people are hiding credit cards, checking accounts or savings from their live-in partners, according to a new study from Bankrate. Another 9 million say they used to have such an account, but have come clean.

Young people are hiding more than other generations, with 31% of Millennials admitting to having a secret account, compared to 24% of Gen Xers and 17% of Baby Boomers.

"Lots of Americans are keeping a big secret that they shouldn't," says Matt Schulz, CreditCards.com senior card analyst. "With any relationship open, honest and ongoing communication is crucial and that is certainly true with money."

Related: How to stop the money fights and grow (wealthy) as a couple

Even if you have room for improvement in talking money with your partner -- as most of us do -- let's hope that you are not among the 11% of people who say they do not talk about money with their partner at all.

"That means a lot of couples have trouble brewing that they have no idea about," says Schulz.

Only a little over half of us think our partner is being honest with us. Naturally, we're more confident in our own truthiness: 61% of us say we're being honest with our partner when it comes to money.

This kind of trouble can be just as devastating to the relationship as other kind of untruths. For 31% of people in the study, cheating financially was worse than cheating physically.

"And the less money you make, the more likely you are to agree that financial infidelity was worse," said Schulz. "Simply because there is less margin for error."

But what's so wrong with stashing a little money?

Fair enough: there are some totally legit reasons why you may hide money from your partner.

It is possible you're stashing away savings to surprise your sweetie with an engagement ring, say, or a trip for your anniversary. Or maybe someone has a hobby they know their loved one looks down on, like that fantasy football league your partner thinks is frivolous or the scrapbooking projects your partner says is burning money.

But it's unlikely that more than a handful of these millions of secret accounts are happy surprises, says Schulz.

Money is fluid and your conversations about it should be as well.

"It shouldn't be a once a year thing," says Schulz. "It should be a part of your ongoing discussions. Maybe you put it on the calendar to talk about once a week or maybe you discuss issues as they come up. But however you do it, you need to be honest."

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