One Roman apologist charges that the Reformers denial that marriage is a sacrament and “hence took God out of marriage, placing it in the hands of the state government.” He charges that the contemporary mess of marriage can entirely be laid at the feet of the Reformers.
On the contrary, James Swan, a student of the Reformers, methodically works over this charge and concludes that the Reformers’ teaching on marriage was something quite different:
Calvin affirms: marriage was instituted by God, and that it is a good and holy ordinance of God. But simply because it holds this pedigree doesn’t mean it’s a sacrament… “At length, we must extricate ourselves from [the Roman church’s] mire…”
This was the gist of the Reformers’ teachings on Marriage – and their message was that the Roman making of marriage into a sacrament, and dependent upon Roman Canon Law, introduced all manners of aberrations that convoluted the true meaning of marriage.
The Reformers on Christian Marriage, Part 1
The Reformers on Christian Marriage, Part 2
If you are interested in defending marriage, I would heartily recommend both articles.