The Second-Best Option
I read this article a while ago that really clarified my feelings on this. Studies show that people who are married are, on average, slightly happier than people who are not married, which has been known for a long time, so people have sort of internalized the idea that marriage equals happiness.
But when you break down the numbers in that, what it actually looks like is that people in happy marriages are much happier than everyone else, and people in unhappy marriages are much less happy than everyone else. So being in a good relationship is the best situation. But being single is the second-best and far better than being in a bad relationship.