Legal Marriage

If governments are created by people, formed when groups of varying sizes come together to establish laws and hierarchies, they are by necessity social constructs because they are not there apart from cultural forces.  A political body could unify in recognition of logical truths, moral obligations, scientific laws, or other metaphysical things that are true or that seem to be true, serving that which is transcendent or at least not dependent on a politician's or citizen's whim.  Criminal "justice" is not made so by democracy or autocracy or any other structure of government.  Forming a marriage, in spite of the traditions inside and outside the church associated with it, ultimately has nothing to do with the government unless people allow theirs to.

Any law or norm established by a government is thus just that: a mere law or norm treated as authoritative by irrationalists.  A thing could be legalized or criminalized, and it is only the real obligation that the law might happen to overlap with which is valid on its own.  Laws are invalid on their own without perfect overlap with real obligations, and rationalistic caution is by no means what marks any of the reported legal systems of the world.  As a consequence of this, legal marriage and even all of its secondary traditions in various countries are looked up to by some as moral necessities for romantic partnership.

Legal marriage is inevitably a social construct.  It could be nothing else.  Since it is a legal marriage, it depends on human law, and human law depends on government, and government is only formed by bodies of people.  There is no legal marriage without some sort of society, making it nothing but a social construct, but there could be lifelong romantic relationships without any governments at all.  Someone can choose to pursue it free of assumptions because they personally want to legally formalize/express their commitment to their partner.  This is not erroneous.  What does not follow is that if romantic commitment to a partner is good, then legal marriage is a moral necessity.

As strictly logical truths, these things do not depend on any examples of how real couples interact or on subjective emotions or on the teachings of the Bible (which are actually in full agreement with these logical facts).  They are true irrespective of all such things.  Anything established by a legal system is nothing more than that even if it is in alignment with something true and deep and good.  A moral obligation to remain committed to one's partner for life outside of specific exceptions would not be made true by human preferences, and any law or cultural norm would be irrelevant to its nature.  Legal marriage simply is not important in almost any of the ways it is held up to be.