When you start lying to your partner about how much you're really spending on a new wardrobe each week, you're probably putting your relationship on the line.

Fifteen percent of people lie tot heir partners about credit card purchases, and one in 10 say it's caused a breakup, according to a new survey conducted by British site, MoneySupermarket.com.

But why are we hiding our swiping habits? More than a third of people said they lied because they knew their significant other (SO) would get angry, while others just had a feeling their SOs would disapprove. It sounds innocent, but these little financial white lies can lead to a split.

“Trust is the number one essential ingredient in a relationship,” says relationship expert Terri Orbuch, Ph.D., author of Finding Love Again: 6 Simple Steps to a New and Happy Relationship. “And that trust can be broken through lying or big omissions.” While this is especially true for long-term couples, it’s also a good tip for new pairs since being financially compatible is surprisingly important. Sure, you can downplay your expensive haircuts, but if you edit or omit information on a regular basis, you’re not giving your partner a realistic portrayal of how you handle money, says Orbuch.

This doesn't mean you need to get your partner's approval every time you're about to swipe the plastic, instead, Orbuch suggests coming up with a threshold amount that you can spend without to consult the other person.