Kinda creepy that a 20 year old adult is married to a 12 year old pre-teen. Switch the genders and I think everyone could see the issue
Yeah, it would be "kinda creepy" (come on, sound off about this if you're going to call it
pedophilia) if the sexes were swapped. Thanks for reminding us about how something that works in one way doesn't work the other way because we have
biases.
...seriously speaking, the culture being depicted is different and the 12 year old is almost certainly already socialized as a man in this particular culture, in this particular era-- if only barely so. It's also fiction, so I don't have to hold real world standards to begin with, and it's clear enough that this detail doesn't
just exist to permit the relationship but is a natural part of the web of standards of the culture depicted.
In terms of writing, I tend to observe that age gap relationships in general are only feasible (read: are not and do not devolve into pornography) when 1) the two parties have relatively similar maturity levels OR the younger party endeavors to match the older party's maturity level, and 2) the older party is passive while the younger party pursues until the older party is won over. Presumably, the point of these conditions is to establish that the superior party isn't using their power (social or physical) in order to coerce the subordinate party and that the superior party is actually quite harmless, which is why these conditions probably apply to teacher/student and boss/subordinate premises as well.
I'm about 10 chapters in, and the relationship satisfies those conditions (well, to the extent they're applicable-- they're already married, but there's still the matter of them growing affections afterwards).