Of course, retirement assets are not just those that exist in a 401(k) plan or IRA. Couples use all sorts of assets to help them plan for retirement.
What to do with the house is a subject accompanied by deep emotions, both from couples and their financial advisors. The way many financial advisors tell it, spouses—especially women—often have an irrational attachment to the home. They often see it as the embodiment of all that was good about the marriage.
Read MoreSudden wealth can leave you broke
"It's the biggest mistake that most women make," said financial planner Candace Bahr, founder and managing partner of Bahr Investment Group. Bahr's not-for-profit organization, Women's Institute for Financial Education, holds monthly divorce workshops at a local community college in the Carlsbad, California, area.
"I call it the marriage mansion," she said. "Women want to keep the home, even if it's not appropriate."
But a house can also be viewed as a retirement asset, argued Sandy Voit, a certified divorce financial analyst with Tangible Solutions. And it's more tax-efficient than other pools of retirement money.