Many studies have shown that a stable and happy marriage is good for the health of both partners, increasing longevity. But did you know that there's also a link between one spouse's happiness and the health of the other?

Building on the idea that a happy person is often a healthy person, researchers from Michigan State University and the University of Chicago explored whether a happy outlook could positively affect relationships. After studying nearly 2,000 couples, they found that people with a happy spouse are more likely to report better health over time — above and beyond their own happiness.

It may be that a happy spouse offers their partner more TLC than an unhappy one who is often focused more on his or her own needs. A happy partner, especially one who follows a healthy lifestyle including regular exercise and smart food choices, is more likely to motivate their spouse to follow their example and become healthier in the process. Also, a happy spouse is likely to place fewer demands on a partner, reducing the likelihood of unhealthy behaviors like drinking.

How can you create a happier environment within your relationship? It's easier than you might think. Showing affection fosters feelings of well-being. These can be physical demonstrations, like kisses and hugs and holding hands as you sit or walk, as well as verbal ones, such as a simple but heartfelt compliment. And who doesn't respond positively to hearing those three little words, "I love you?"