NEW YORK (CNNMoney.com) – Having one of those jaw-clenching financial "discussions" with your (spendthrift, tight-fisted, financially clueless or controlling) spouse?

Well, you'll be happy to know that many successful marriages are generously seasoned with episodes of anger and disagreement.

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At least that's what psychologist John Gottman and his team at the University of Washington have found after conducting extensive research on married couples in what is often called "the love lab" -- where researchers observe a couple's communication styles and physiological changes during conversation to help predict whether they're likely to divorce.

"(I)n the ecology of marriage a certain amount of negativity is required for the union to thrive," Gottman writes in his book, "Why Marriages Succeed or Fail." "(A)iring a complaint -- though rarely pleasant, makes the marriage stronger in the long run."

Of course, there's a caveat.

In marriages that thrive, that "certain amount of negativity" isn't the embittered, permanent variety that's infused with truckloads of contempt, defensiveness and stubbornness.

Here are some key signs that your money fights are moving from healthy to toxic for your relationship, according to Gottman:

You criticize, attacking your partner, not just a specific behavior. "I wish you'd pay the bills on time, so we can avoid paying late fees" is a legitimate complaint. Saying, "Why can't I ever trust you to pay on time?" is criticizing.

You show contempt, insulting or psychologically abusing your partner. During an argument about spending, a wife says to her husband, "Why are you always so irresponsible? You never pay attention to how much you spend. You're so selfish."

Also relationship poison: hostile humor and mockery.

You're defensive in response to your spouse's contempt. Who can blame you, right? But as you know, "being right" and keeping your spouse happy are two different things.

So if your spouse spews something like, "You never want to spend money on vacations," try not to fire back, "Yeah? Well you never want to have sex."

You start to stonewall. Next time a money fight starts brewing, you indicate in far more colorful language than I'm allowed to use here that you've had it and then walk away.

There are small (although I'd hardly call them easy) things you can do to curb excess negativity when it seeps into your arguments.

For starters, keep a complaint specific. Gottman advises making an "X,Y,Z" statement as in: "When you did (or didn't do) X in situation Y, I felt Z."

"It's more constructive to say, 'When you bounced several checks, and the bank called, I felt embarrassed and angry' rather than 'You're incredibly irresponsible for bouncing a check, I'm constantly have to pick up after your mistakes and fix everything you screw up,'" he writes.

And when a disagreement turns into a power struggle, the argument is likely to go a bit better if you keep in mind that "listening is not obeying," said Diana Mercer, an attorney and mediator with L.A.-based Peace Talks Mediation Services.

Stable couples, Gottman found, also employ "repair mechanisms." They include empathic comments like "I see" or "Uh huh." And they may include comments that can curb the negativity such as, "That's off the subject. We were talking about how to keep the house clean, not whether we can afford a vacation."

Apparently, these little checks need not be delivered in the sweetest of tones either. Thank goodness for that.

You'll also be glad to know that it's not always a bad thing if an argument about money makes you just want to throttle each other or, conversely, bury the issue and take the dog for a walk.

Successful marriages often are achieved when couples share one of three fighting styles, Gottman has found:

• You're both volatile, airing your grievances early and loudly

• You're both avoiders, agreeing to disagree and move on; or

• You're both validators, acknowledging each other's feelings even if you think they're crazy (just don't say that).

These styles can help you navigate through your financial arguments even when you have completely divergent views.

Writes Gottman: "My research shows that much more important than having compatible views is how couples work out their differences."

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Jeanne Sahadi writes about personal finance for CNNMoney.com. For comments on this column or suggestions for future ones, please e-mail her at everydaymoney@cnnmoney.com.