Early on in my marriage I did everything I could to hide my infidelity. No, I wasn't cheating on my husband, at least not in the way you think. I was spending beyond our means behind his back.

My infidelity took some organization. I rented a private post-office box to hide my indiscretions -- those bills for things I shouldn't have bought. I cut tags off of new clothes and kept recent purchases in the closet for a while so I could honestly swear they weren't new.

While being sexually unfaithful to your spouse can certainly create an industrial-strength barrier to financial harmony, financial infidelity, the kind I'm talking about, is the subject of many letters I receive as editor of Debt-Proof Living.

"Dear Mary," one begins. "Is there any hope for my situation? I have run up more than $75,000 of credit card debt. My husband doesn't know about this and I will never be able to tell him. It takes my entire payroll just to make the payments on this debt, and it seems like I'm getting nowhere with it. What can I do? I don't want to file bankruptcy, but I'm beginning to think this is my only way out. Please help me."

While not all financial infidelity is as serious as $75,000 of hidden debt (or the $100,000 I ran up), money secrets between spouses can grow into barriers of serious proportion. Money secrets destroy trust.

Such cheating doesn't always occur on such a grand scale -- and it's more common than you think. Many spouses have a closely guarded secret. They launder money. I know how this works both from personal experience (something I’m not proud to admit) as well as from years of communicating with both husbands and wives.

Launderers think they're being smart. They hide cash to avoid arguments over money, figuring it’s easier to skim than to face the hassle.

A wife writes a check for more than the grocery bill and receives cash back. That’s cash her husband cannot trace. As far as he's concerned the checkbook says the groceries came to say $112.08. In truth, the tab was $82.08 and she pocketed $30 to cover the cost of a pedicure, an expenditure her husband does not understand. She believes it just saves an argument to do it this way. She gets her pedicure and he’s none the wiser.

Men launder money, too. Here’s a typical example: He lunches with colleagues, puts the entire tab on his credit card and collects cash from the rest of the party. The money goes into his wallet and the charges wash out in the credit card statement where they are buried along with the names of several other restaurants. She’s none the wiser and he has a pocket full of secret spending money.

So you might ask, is laundering money or "skimming" wrong if the real reason behind it is to eliminate arguments and keep the peace? Consider this: If your business partner were sneaking money out of the business by laundering it or just skimming it out of the till with the sole purpose of deceiving you, would that be wrong?

This is pretty simple: Laundering is lying, so yes it is wrong. More than that, laundering money in the ways suggested above or skimming it off when no one is looking, will build walls between the two of you and eventually sabotage emotional intimacy. So there goes the trust and if you don’t have that, what’s left?

Bottom line: If laundering and or skimming are going on in your marriage, it's a problem and must stop. This doesn’t mean that you or your spouse will never have any money to call your own. I suggest that each of you have an amount you both agree to call it your allowance.

Let’s say you agree that each of you have $300 a month to call your own. You can save it, spend it, give it away, have 10 pedicures -- anything you want without having to account back to your spouse for its final disposition.

Both of you are fully aware of your allowances so it fulfills two purposes: A strong partnership where everything is known to both partners and a sense of autonomy that you are adults with the ability to make independent financial decisions without having to ask permission for every little thing.

Okay, back to the issue of financial infidelity. My standard response to letters I receive from the woman who has racked up $75,000 in debt without telling her husband: Imagine for a moment that it’s not you, but your spouse, who wrote to me.

How would you want me to respond? Shall I tell him to just keep quiet and do the best he can so you never find out? Or would you want me to plead with him to confess with total remorse and a willingness to make things right?

In all the times I’ve heard a response to that question, no one has responded with the same answer they’d like me to give his or her spouse. Just thinking about the situation in those terms helps the letter-writer see what must be done.

Following are the steps I offer to anyone in this situation.

Acknowledge the offense for what it is: betrayal and deceit. Financial infidelity is not occasionally forgetting to record a check or an ATM transaction. Financial infidelity is consciously and deliberately lying to one’s spouse about money, credit and or debt. Tell it like it is. Don’t argue, justify or debate the issue.

Adapted from Mary Hunt's book Debt-Proof Your Marriage.

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