This question is somewhat deceptive. I say this because many people are fornicating their way through "trial marriages" a.k.a cohabitation, yet they are not married. They may even have children outside of the marital union.
For those couples living in sin through cohabitation, they are still likely to feel the effects of "divorce", upon breaking up, especially if children were a result of their union. If you are a man, get ready to pay child support. If you are a child, get ready to get thrown into day care.
About the only way to win in the "singles" game is to use your freedom to serve the Lord, but one must play by the rules. This means no fornicating and using your freedoms to be a "playa" or to be selfish and self-serving. If this is the case then you are far better off finding someone whom you can love and someone who can love you.
Not getting married does not necessarily save you from the pitfalls and perils that often plague marriages.
So, I would say in its truest sense, that there are probably not a whole lot of disadvantages to marriage, if one chooses wisely. To stay unmarried would only be beneficial if one were on some kind of spiritual quest or answering a higher calling.