Marriage means a lot of different things to different people. For some, it does mean creating a family—at least, at some time in the future. Many couples will postpone children for periods of differing lengths of time. Some want to be married but they never want children.
So, for your first issue—marriage does not have to mean children. It is possible to marry someone not for the purposes of raising a family, but for other reasons.
This is confounded, though, for people with certain religious beliefs. Some believe that marriage is for children, and if you don’t want children, you shouldn’t get married. I guess is someone believes that and they don’t want children, they shouldn’t get married—at least, not until they want children.
Other people want to marry and have children eventually but not now. They have many birth control options. But some people don’t believe in birth control. Including so-called natural birth control. I think this is probably pretty rare. But people have all kinds of beliefs.
It’s hard for me to imagine being in such a situation, because it seems like you are deliberately putting yourself in an impossible situation. I think you have two choices—marry and don’t try to avoid children, or don’t marry and don’t ever have sex.
There are a number of people in the world who have eschewed marriage—at least to another person. Priests and nuns of some denominations are supposed to avoid sex with other people, and they are not allowed to marry. They are married to God or to the Church or something, instead. Who knows how many of them actually stay celibate? In any case, that’s a model for a marriage without children and without sex. It’s a metaphorical marriage, and I suppose that if that was of value to someone, or to two someones, then they could get married and not have sex. Again, I think this is quite rare.
I don’t understand why celibacy is important to some people. I do understand why remaining childless is important to people. I don’t understand why some people think that marriage is for having children, and that’s it’s only purpose. I don’t understand why some people believe that birth control is forbidden by their belief system. It seems to me like it would be a very twisted and confusing set of beliefs, and people who had those beliefs must have a hard time with life. But hey, different strokes for different folks. As long as they don’t try to force me or anyone else live by their rules, I’m happy to leave them be.
I think your scenario must be pretty rare. It seems like it would be an arcane religious practice. It seems like it would really mess with a person’s head. I can’t imagine that very many people would voluntarily take on such a challenge. I hope this is just an intellectual exercise, and not something you or someone else is actually considering.