simcha613: When the constitution was written, the government didn’t allow anyone to marry – it was still governed by religious law (Jews by halacha, Christians by the Canon law of the established church – meaning Jews could divorce easily and Christians were married for life). They were just then taking the canon law of the Church of England and requiring everyone to marry according to that one law. At that time, it was a crime to have “relations” outside of marriage (thus the phrase “making it legal” as a way of saying one is getting married), and when they changed that law, they seriously undermined marriage law. Subsequent to the constitution being adopted, they also made it possible to divorce easily and gave the children of unmarried parents rights (in 1789, such a child was considered an orphan with neither a mother nor a father).
I strongly disapprove of legalizing gay marriage, but you run into a lot of problems by asking what was intended in 1789.