Do you know what your spouse makes? 43% of Americans don't

(Bloomberg Business) — In the constant struggle to balance family finances, many Americans have a problem: They don’t really know how much money their spouses are bringing home.

In a study of 1,051 couples, Fidelity Investments asked people how much their partner earns. More than 40 percent got the question wrong. One in 10 misjudged their partner’s income by more than $25,000.

So far, the 21st century hasn’t exactly been easy on middle-class finances, and couples’ failure to communicate may be adding to the anxiety. If you don’t have a handle on how much your household earns, it can be hard to feel in control of your spending. Fidelity also found more than half of people worry about outliving their retirement savings, up from 42 percent in 2013.

Couples’ ignorance about their incomes seems to be growing, from 27 percent in 2013 to 43 percent this year. You can blame that on poor communication, says Fidelity’s John Sweeney, but the changing economy may also be a culprit. Many workers now move from project to project as freelancers, or they work second or third jobs with unpredictable hours and pay — think Uber drivers. That gives them only a fuzzy idea of how much they’ll make by the end of the year. Others are getting more of their salaries in bonuses. An end-of-the-year bonus is always welcome, but you can’t count on it.