Bono wrote the lyrics to the song "Two Hearts Beat as One" on his honeymoon, and his band U2 premiered it in 1983: "Two hearts beat as one ... The way I feel ... Oh, yeah, two hearts."

That romantic joining can make life sweet. But if you're not careful, it can also put you at big-time risk for heart disease.

A new study presented at the American College of Cardiology's 70th Annual Scientific Session shows that when one spouse has heart disease — a heart attack or stroke, or surgery such as coronary artery bypass — it more than doubles the risk of heart woes for the other.

The study looked at 5,000 heterosexual couples and found that 28% of men whose wives had heart disease also had the condition, compared with around 13% of men whose wives did not have heart disease. And 21% of women whose husbands had heart disease also had the condition, compared with only 9% of women whose husbands were heart-healthy.

Fortunately, when shared lifestyle habits are the cause of the heart problems, there's a lot you two can do to get heart-healthy.

One of the simplest solutions, according to a new study in the European Journal of Epidemiology, is to eat 1 cup of nitrate-rich green leafy vegetables a day. Spinach, bok choy, and arugula are great sources.

That will help lower your blood pressure, bringing the top (systolic) number down by 2.5 mmHg. It will also lower your risk of heart disease by 12%-26%.