I asked the penguins and they stated they use domestic partnership, not marriage. They said it’s foolish to get people hurt fighting for something like a word.

The term marriage didn’t even exist back then, just the union going by other terms, maybe find one of those terms if you think the tradition of a word matters more than the happiness and safety of the population. Looking it up, It appears most people just called them unions. So we can put domestic union into the documents instead of marriage. That should solve your issue.