While marriage and long-term relationships tend to contribute to longevity, satisfying friendships are key to a happy life. Friends come and go. Some stick with you forever, and others part ways when you least expect it. No matter how satisfied you are in a relationship, having a social life is essential for overall well-being. Study links happiness to satisfying friendships Being single is a lifestyle choice for many adults and a large percentage of the American population is consciously choosing not to be in a long-term relationship. Plenty is said about love birds who live happily for the r…