The key to staying happily married is to fight--just a little.

1. Money
2. Household chores
3. Work obligations
4. Kids
5. Differing priorities

Interestingly, fully 69 percent of disagreements that arise in a marriage are never resolved; they really are irreconcilable differences, reports The Wall Street Journal. If this is true, then researchers insist there is no such thing as a compatible couple. But that doesn't mean people can't find happiness in marriage. They just have to learn to manage their differences.

"Compatibility is misunderstood and overrated," Ted Huston, a professor of psychology and human ecology at the University of Texas at Austin, told Wall Street Journal reporter Hilary Stout. In a long-term study, he followed 168 couples who married in their 20s during the 1980s. Each couple was interviewed two months after their wedding, as well as 14 months, 26 months, and 13 years later. They were specifically asked about two issues that can derail any marriage:

• leisure interests and
• expectations about who should do what around the house.

Huston found that after 13-1/2 years, 105 of the 168 couples were still married, while 56 had divorced. The remaining seven couples were widowed or couldn't be located.

Here's a surprise finding: The couples who divorced "were not less similar" in either category.

So if most differences really are irreconcilable, how does anyone get along? Marriage therapists are now changing how they counsel couples in trouble. Instead of helping them resolve arguments, they are helping couples manage, accept, and even "honor" their discord, reports the Wall Street Journal. One program even tells couples to schedule a weekly date--to argue!

• Don't use sweeping generalizations, stay on the subject, and don't bring up past events or behavior.
• Do not interrupt each other.
• Give yourself time to cool down after an argument. Then be sure to have a productive reconciliatory conversation.