Marriage was recognized as between one man and one woman at the time the Constitution was written and the Founding Fathers saw no conflict in the matter.
FWIW, I’d say the concept of homosexual *marriage* was something that never even entered their minds.
The word “homosexual” was coined about nine decades after the Founding Fathers set out to create the USA. The very act was unmentionable to them, never mind “abolition of the family” as Marx termed it.