What purchases spouses hide from each other

(MONEY Magazine) -- You'd never want to outright lie to your spouse about your spending, but if a little fudging may help avoid a fight, what's the harm? Or so you figure.

Some 80% of all married people hide some purchases from their mates, according to a 2010 survey by CESI Debt Solutions. (And men are actually somewhat more likely to routinely do so than women.)

But just because it's common doesn't mean it's right. Experts say that little green lies do have the potential to damage your finances and your relationship. Fortunately there are ways to keep your marriage whole without revealing every dime you spend.

Putting aside any pathology (like an addiction or compulsion), the reason most couples hide what they spend is simple: "You're avoiding conflict or criticism from your partner," says psychologist Brad Klontz, co-author of Mind Over Money.

Most money fights start with finger-pointing -- "How could you spend $300 on a new sweater/Blu-ray player?" -- but the object and price aren't really the issue, Klontz says. You're really arguing about a clash of values. Rather than talk about these differences in advance of buying something, it's often easier to sweep purchases under the rug.

Given that fudging may prevent fights, you might argue that there's a place for discretion, and you'd be right -- up to a point. "All couples need privacy," says Barbara Nusbaum, a New York City psychologist who focuses on money issues. But you must balance that need with the need for accountability. "Not telling is fine," adds Klontz, "as long as you don't start deceiving."

Some couples manage their spending without sharing anything, Klontz explains. If they've agreed to operate autonomously, that's acceptable. On the other hand, choosing not to tell your spouse about purchases without an explicit agreement to practice nondisclosure is a form of deception, he says, and that can be ruinous to the relationship.

If you're not sure where your behavior falls, "ask yourself, 'If my partner found out, would this damage the trust between us?' " says Nusbaum. The most dire signal is that your habits are hindering progress toward your common goals. Other red flags: You hide bills or receipts, you have an account your mate doesn't know about, or you've involved the kids by saying, "Don't tell Mom/Dad."

Every couple should articulate a privacy policy -- whether that means a dollar amount you can spend at one time, a monthly stash of mad money, or certain categories (kids or work expenses) that don't require discussion. Then set up a trial period of 30 days, says Klontz, "because you'll probably want to renegotiate."

If one or both of you have a long history of hiding, you'll also need to discuss the gap between your values. Don't dwell on purchases or amounts, says Nusbaum, but each express what's behind your spending, like helping family or enjoying down-time. That can aid understanding.

Above all, you must accept that you may never fully persuade your partner over to your side of the aisle -- which is why, Klontz says, "it's important to stop trying to convince each other and move toward a workable compromise."