Why People Shop on the Sly

Seek Financial Counseling
If you can't seem to resolve money issues together, consider bringing in a third party for help. A meeting with a financial counselor or adviser can help answer your questions and put you on a healthier track with your budget.

Attend this meeting together so that you're both attuned to your overall financial picture. "Couples that won't honestly talk to their partners about spending will open up to us because they feel safe," Ellington says.

Agree to Disagree
Finally, recognize that you and your spouse don't have to agree on everything when it comes to spending and saving money, and you'll likely each need to make compromises.

If your money personalities clash, strive to find a middle-ground solution that makes you both reasonably happy with the outcome. Don't make money matters a competitive winner-take-all contest. Acknowledge that you both have different ways of managing money, without insisting that one person's approach is "right" or "wrong."

If you're the one who's been hiding purchases, realize that it's probably best to come forward and broach the subject of secret spending before your spouse finds out and confronts you over the issue. You don't want your partner to feel betrayed. According to the CESI survey, 30 percent of those polled said financial infidelity is just as bad as sexual infidelity.

But for those of you worried about coming clean with your spouse, take heart in knowing that the odds are in your favor that love will prevail over your past financial indiscretions.

Despite financial infidelity, 60 percent of married couples say they would still forgive a spouse for secret spending.

Lynnette Khalfani-Cox is the author of  Perfect Credit: 7 Steps to a Great Credit Rating. You can friend her on Facebook or follow her on Twitter @TheMoneyCoach.