Beyond the emotional implications, marriage can also carry a number of financial ones, but despite this fact, nearly half of married people don't know how much their spouse makes, according to CNN Money. Fidelity bank, surveying married people, could not correctly guess their spouse's income 43 percent of the time. They weren't even asking for an exact dollar figure accurate down to the last cent: the survey only asked what income range their spouse was in. Of those who got it wrong, 10 percent got it wrong by more than $25,000, according to CNN Money. The survey also found that men and women were equal in not knowing how much their spouse makes. 

CNN Money notes that this has implications for personal budgeting: namely, how can a couple set a budget if they don't even know how much money they have to work with in the first place? Consider, too, that money is generally considered to be one of the biggest sources of strife between couples, which perhaps could be exacerbated by not even knowing how much money the other person makes. 

What's more, the number of people getting their spouse's income wrong has risen 16 percent since Fidelity last did this survey two years ago, something that Fidelity thinks could be attributed to more people being self-employed, which can lead to inconsistent incomes, and the bull market, which can drive up annual pay for certain professions.