Before questioning someone’s marriage, you should question the institution of marriage itself. How was it formed? Why was it made? And how the world was operating before this system?
Isn’t it strange that almost all civilizations and religions adopted marriage by default – with a little this and that? Why?
How people lived otherwise? Were there more matrilineal societies?
In the end, wasn’t it the element of jealousy that formed an institution to bestow property kinda laws on people and their sexualities? Particularly women!
If your answer is all about procreation and children then what if the state takes the position of a father – as Plato said? It had. And it has.
Education, health, monthly payments to mothers and similar other services by the state can defuse your arguments for marriage. See Scandinavia. The state owns its children more than a father.
By the way, don’t get into answers where marriage is confused with parenthood. Parenthood was always there. Marriage wasn’t. Even today in certain tribes, marriage is not known.
Now, that would be a long post. Maybe some other day with some insights from Bertrand Russell.
But before that, you must read the last post about 1799 which you people have intentionally or unintentionally ignored.