That’s what happens when you let the government intrude into (and inevitably mess up) a societal institution.
But Government at the State--certainly not Federal--level has a quite clear role, here. It is not the same role as that of Religion.
The role of religion goes to the spiritual sanctification of the union. The role of the State goes to such things as rights of inheritance; rights to civil protection for the privacy & the aspects of a marriage that relate to a certain level of legal autonomy.
In the one case, are considerations of all things that pertain to the spirit; in the other, to all things which relate to the social & economic order. They overlap; but they are not coextensive.
William Flax