Forget about lying, sexual incompatibility or infidelity. The real threat to your relationship may be your (or your partner's) tendency to splurge on things that are outside your budget. As I often explain on Facebook, Twitter and in my financial seminars, the consequences of rampant over-spending -- especially when using credit -- are enormous. Not only are credit card delinquencies, bankruptcies and foreclosures on the rise, debt is even a huge factor in families being split apart.

Studies show that seven out of 10 couples who divorce say that financial strife played a big part in the breakup. If you're married, be honest with yourself for a minute. Have your partner's spending habits or financial patterns ever driven you crazy? Or perhaps you actually need to look in the mirror. Does your way of handling money – maybe buying things that the two of you can't afford – cause friction in the relationship?

It seems like a cruel joke of the universe that so many couples are financial mismatches, with one person being a care-free spender and the other a staunch saver. Perhaps that's why, in a study of 50,000 couples who went through its marriage preparation course, Life Innovations found that 72% of the 100,000 individuals polled said they wished their partners were more careful about spending. Also, 56% said major debts were a problem in the relationship.
So, I don't care how romantic things get between you and your honey in the bedroom. It's what happens at the kitchen table, when you're going over the monthly bills, that can more accurately forecast the success or failure of your relationship. Do you communicate well about money issues? If so, chances are you can talk freely about other things, too. Are you overly critical or unfairly judgmental about how your partner handles money? Then you're probably equally judgmental about non-financial topics.

Trust The Money Coach on this one: If you don't take the time to straighten out money issues, no matter how large or small they may be, these conflicts will continually surface, and they'll haunt you for the duration of your relationship.

I know you might have vowed "until death do us part" after you walked down that aisle. But if you're not careful, that once-happy marriage can unravel over money battles. Don't let your relationship turn into a case of "until debt do us part."

Need to get out of debt? Check out my book, Zero Debt: The Ultimate Guide to Financial Freedom. My husband, Earl, and I don't agree 100% on all money matters. But on this we do agree: It's our goal to constantly strive for a debt-free lifestyle, and not let money issues -- or anything else -- ever tear us apart.

Have debt or money matters ever come between you and a loved one? Sound off on this topic below. You can also follow me on Twitter, @themoneycoach.

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Lynnette Khalfani-Cox, an award-winning financial news journalist and former Wall Street Journal reporter for CNBC, has been featured in the Washington Post, USA Today, and the New York Times, as well as magazines ranging from Essence and Redbook to Black Enterprise and Smart Money. Check out her New York Times best seller 'Zero Debt: The Ultimate Guide to Financial Freedom.'