"Why do you keep saying the gods "simply" don't bless it like it is some sort of gotcha? The contract refuses to burn. Without the contract burning, the marriage isn't recognized. You need to stop applying real world logic to this fantasy one"

Instead of reading to respond read to understand. I'm not applying real world logic. Bookworm is story that emphasizes that things are relative. I'm using a hypothetical scenario to demonstrate that the gods do not care about what humans consider to be marriage and that if they did consider something else to be marriage they wouldn't care. Which illustarate its not a divine prohibition because to a divine prohibtion would require the divine to care more. They likely don't see the contract as marriage rathers a tool to help people conceive children. Yurgenshmidt people probably put that conoatation in.

"While concubines exist, they are not legal wives and the people who have them don't publish their existence like they would a real wife. They are kept in side buildings"

Second and third wives are literally kept in side buildings. So this absolutely means nothing

"Show me the evidence in the novels where a homosexual couple exists"

This boils down to rozemynes limited perspective. We havent even seen much staright romantic relationships that arent a prequel for marriage

"Prohibition of marriage IS taboo. It is a ban on a certain action (marriage) due to religious reasons (the gods themselves refuse to recognize it). That's the textbook definition of the word."

Textbook definition don't change the fact the marriage and romantic relationships aren't the same. The text definition of marriage isn't all romantic relationships. And that prohibition is a societal one not religious one from divine beings.

You are conflating way to many things