Any government that assumes the role as the final arbiter of private, religious associations and contracts between individuals represents the antithesis of a free society. A country that delegates upon itself the authority to approve or disapprove of the relationships between individuals who love each other, is not free and cannot identify itself as a place of liberty.
You have defined the bottom line.
My brother and I are adult individuals who love each other. According to your statement above we should be free to marry and reproduce. Is that what you meant?
My husband, my best friend and I are all adult individuals who love each other so according to your statement above the 3 of us should also be free to marry each other as one unit. Is that what you meant?