Marriage developed organically as a religious institution. In 2015, in Obergefell v. Hodges, the United States Supreme Court admitted that, at least for the first fifty years of the United States, that marriage was a purely private contract the somehow morphed into a public one. This was Free Market Marriage, something consistent with the Founding Documents. America was founded on two principals: Consent/Agreement and Religious Liberty, Commerce and Religion. We fought a Revolution to separate from a theocracy, a nation where status depended on your faith, your beliefs. Therefore, couples married in their faith, entering into private agreements with each other and their religious leaders.
The Crown recognized only those married within the Anglican faith, who married in the Anglican Church. Thus, George and Martha Washington were legally married, but Benjamin and Sarah Franklin were not because they were Quakers. A Google search still shows that the Franklin marriage is still considered Common Law. The United States Constitution eradicated that distinction. In 1877, the Supreme Court affirmed that marriage was a private contract, yet eleven years later, four Justices would claim that marriage had always been under control of the State, giving the State the same power as the King. How? In England, the King had two roles. He was Head of State and Head of the Anglican Church. In the latter role, his consent was necessary for anyone marrying in the Anglican faith. Therefore, in England, at least for those who married in the Anglican Church, marriage was "not an ordinary contract." The Court then said the State was the same as the King and therefore, marriage in America was not "an ordinary contract" leading to State regulation. The Court adopted the law of the Anglican Church as the Law of the Land.
Based on that decision, for the next 90 years, State Courts and then State Legislatures developed modern Family Law out of whole cloth based on the laws of the Anglican Church and the principles of Chivalry. Then, beginning in the 1960s, those who were anti-religious took power and have been attempting to destroy what had been a religious institution in the name of freedom. How? By enforcing the duties of the Anglican Church only for men, but not for women, thus encouraging women to divorce and to have children out of wedlock, causing men to drop out of the marriage marketplace, also leading to a vast reduction in church attendance.
Restoring marriage to a purely religious institution will open up the marriage marketplace and restore America to its Judeo-Christian roots.