12 million Americans may be hiding a secret account from their partner

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Millions of Americans aren't being upfront with bae about their finances, according to a salacious new survey from CreditCards.com.

Instead, they're committing what is known as "financial infidelity" by keeping either a major credit card or bank account secret.

About 5% of respondents to a phone poll of 1003 adults across the country admitted that they have a secret account of some kind. Creditcards.com extrapolated those results to reach its estimate that some 12 million people are hiding a credit card or bank account from their partner.

Another 24% of people polled said they were okay with their partner dropping $500 without telling them.

"Some secrets can be okay, or understandable," CreditCards.com analyst Matt Schulz said. "There could be the guy who is putting some money aside with his live-in girlfriend to save for an engagement ring."

But not all of these secret accounts are a good idea, Schulz explained, particularly if they're being used on big ticket purchases.

Even if the secret account isn't being used on an something scandalous, it can still create problems. Lee Jin-man/AP

The trouble with money secrets

"I’m kind of fascinated by how much people spend without telling their partner," Schulz said. "We found that about one in four folks folks say they’ve spent $500 or more without telling their partner."

The problem with spending that much money without your partner knowing, he says, is that it throws a wrench into your household budget

In other words, even if you're not dropping the cash on, say, an Ashley Madison account, this kind of behavior can still create problems if both partners don't know how much money is coming in and going out. 

"If you make a lot of money, then a $500 surprise expense may not rock your world. But for most Americans, having to account for that much money that’s missing from their budget is a really big deal."

How to talk about money with your boo

The key is to start talking about money before things get really hairy. 

After all, it's a hell of a lot easier to talk about whether you're putting enough away for a vacation or a honeymoon than it is to talk about why you might be short for next month's rent. 

And while Schulz concedes that comparing finances is "probably not second date conversation," you'll have to get around to it sooner or later — ideally "once you're really starting to think long term about that relationship."

A few ways to make the convo a little less awkward? 

Experts recommend keeping conversations regular and using some sort of impartial "referee," whether through some sort of financial adviser or app

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