Countercountercounterpoint: if it's imperative then how did people perpetuate society before governments?
Government's only role is to enforce contracts between consenting individuals. They got no business dictating the terms of the contract or changing those terms when the contract is violated. Both practices are so common for marriage contracts that people actually believe it's good and right. It is not.
What do you mean "before governments"
People have always been governed by those in society with power.
It is imperative that governments support the building blocks of the society they purport to serve. That does not imply that those building blocks require a government to support them.
I would argue that those marriages are better off in a supportive environment so it is mutually beneficial, but it is not a requirement.
In the other direction I don't think a society can last more than a handful of generations without marriage, thus from the governments perspective, it is absolutely imperative.
