wrong. wrong. wrong. wrong. this is the central truth that you don't accept, and because of that your whole concept of what "marriage" is is skewed. this is where you fundamentally overturn nature, and morality, and thousands of years of socialization.
if you hold that marriage isn't about children, then you are arguing that marriage is simply about two people coming together to have sex with each other and to benefit only each other. it makes it INTENSELY and exclusively a selfish institution. it exists solely to benefit one or the other or both partners in it, that's all. it is narcissism. it is selfishness.
when you raise marriage to be what it has become (before the 20th century has worked to debase it), it becomes an essential social construct that is beneficial for the species and for society as a whole. it is intensely SOCIAL. it exists both to help and benefit the two partners, and just as importantly, to create and benefit new life that helps society. not every man and woman can come together to produce children. but men and women coming together to produce children is the necessary precondition for the creation of life and for the continued survival of the species. marriage is one of the constructs that has raised humanity above animals in the sense that that process isn't just about running around fornicating to scratch our biological urges- like animals do. marriage humanizes us. it elevates us.
and women- i ask you to consider- how has the institution of marriage been beneficial to the advancement of your gender?