80% of couples disagree when it comes to retirement planning

— -- If the economic downturn has forced you to rethink your plans for retirement, it's a good idea to discuss your concerns with your spouse or partner. Before you have this conversation though, you might want to clear the room of sharp objects. That way, nobody gets hurt.

In many households, it appears, retirement is an even more contentious topic than politics, religion or whose turn it is to walk the dog. A study by Fidelity Investments found that more than 80% of couples disagree about a major component of their retirement planning, such as the age at which they plan to retire, whether they'll work in retirement or where they'll live after they retire.

Fidelity found similar results when it conducted a couples survey in 2007, but now, the stakes are higher. Many couples in their 50s and 60s have seen their home equity evaporate and their savings diminished, forcing them to work longer or scale back plans.

That certainly seems like something couples should talk about, but that's not happening. Fewer than 40% of couples said they discuss investments in their retirement savings plans. And fewer than half said they make joint decisions about day-to-day finances, such as budgeting and paying the bills.

"People need to save more, and in order to do that they need more knowledge of their expenses and investments and together what they want out of their retirement," says Kathleen Murphy, president of Fidelity's personal investing unit.

Financial planners weren't surprised by these findings. David Kay, a financial planner in Dayton, Ohio, says that among the couples he advises, one spouse usually assumes primary responsibility for the household finances.

"Generally, it's a result of personal preference," Kay says. "One of the two tends to be more interested in the financial dynamics of the family." The less-interested spouse, he adds, "is more than willing to pass on those duties. As a result, there isn't much conversation between the two individuals when it comes to retirement planning."