The No. 1 thing successful married couples never do with their money

When you say "I do," it's a vow to share everything with your partner: Your fears, your dreams, your home, and even your money.

Deciding how to combine your finances with your partner's includes myriad practical aspects - Should we get a joint bank account? How much should we save for retirement? - but much of the money conversation comes down to a non-monetary factor: communication. Successful married couples make it a priority to talk about their finances and stay on the same page.

In the same vein, the No. 1 thing successful couples never do is hide their money habits from each other.

"Don't hide anything from your partner when it comes to your finances," says Pamela Capalad, CFP and founder of Brunch and Budget. "This includes secret stashes or big debt or a low credit score or a major tax liability. They will find out one way or another."

Successful marriages start with couples putting everything on the table.

"They're transparent, they're open, they're honest," Michael McNulty, a Ph.D. at The Chicago Relationship Center and Master Trainer with The Gottman Institute, told Business Insider. "There's an ongoing dialogue, people know what's coming in, what's going out. There's a strong sense of trust."

As soon as they get married - or ideally, before - couples should show their entire hand to their partner. That means coming clean about their salaries, credit card debt, student loans, credit score, and anything else that might affect their financial future as a couple.

"They should sit down and have a very open and honest discussion about their money and what they have," Pam Horack, CFP and "Your Financial Mom" at Pathfinder Planning LLC, told Business Insider.

From there, it's imperative to keep the dialogue open so that both spouses feel comfortable talking about finances and bringing up related issues at any time.

This trust and openness becomes especially important when one party messes up. If one partner forgets to pay a bill or overspends on a silly purchase, they should be able to tell their spouse without fear of retaliation or judgement. No matter how big or small the transgression, the prospect of coming clean should never induce fear.

"If people can't trust each other around money, more than likely, they can't trust each other about a lot of things," McNulty explains. "Money is such a basic thing in a relationship, both partners depend upon it to survive. Trust is so very important, so couples that hide things from each other around money don't do well."

Understanding how your partner developed their philosophy toward money is also crucial in finding common ground and developing compromises that work for both of you. Was money tight when they were growing up? Had they been deceived about money in a prior relationship? Has handling money been an issue for them in the past?

"If you get those stories back and forth, often it's easier for partners to understand one another," McNulty says.

Talking about money is hard, and getting to a point of complete openness will likely require difficult conversations, but it's worthwhile to prevent financial issues from stretching into other areas of the relationship.

"There is a lot of embarrassment and shame when it comes to sharing your money situation," Capalad says. "It can represent mistakes you've made in the past, decisions you regret, and take a big toll on your self worth. These are all feelings you should be able to share with your spouse and work through together."