I didn't say you couldn't be married and happy, I said that marriage doesn't necessarily lead to happiness. The relationship between the two is complicated and has been studied extensively.

The relationship between marriage and happiness is, like most things in psychological science, bi-directional. In other words, it’s what you do to foster happiness as an individual and a spouse that makes a difference, not marriage all by itself. “Marriage doesn’t make you happy,” says Harvard psychology professor and happiness expert Daniel Gilbert. “Happy marriages make you happy.”