MAINE, USA — A new 15-year study reveals husbands are happiest when their wives contribute a specific amount of money to the total household income. 

The study, which was done Dr. Joanna Syrda, a University of Bath economist in the British institution's School of Management, included over 6,000 American couples and found that husbands are extremely stressed when they have to pay for all the household finances, but are less stressed if their wives earn around 40% of the household income. 

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But, if the women’s earnings exceed that percentage, the husbands became more anxious, according to the study.

"The consequences of traditional gender role reversals in marriages associated with wives' higher earnings span multiple dimensions, including physical and mental health, life satisfaction, marital fidelity, divorce, and marital bargaining power," said Dr. Syrda.

According to the study, in relationships where the wives already earned more money than their husbands before they got married, the men do not experience any stress about their spouse’s higher income.