The sixth law of the lineage concerns the family rules for entering into unions, and what it is about is consent. What counts as the error is a marriage entered into through deception, under coercion, or out of a calculation the other party was never asked about — and also promises given to the family and broken immediately after the wedding.
The origin of a spouse has nothing to do with this law and is not an error in any sense whatsoever. Only one thing matters: whether both sides knew what they were entering into, and whether both had a choice.
In a descendant this reads as a recurring lack of freedom in relationships: marriage "because one has to", the feeling of a transaction instead of closeness, terms that were never agreed out loud.
The working-off is to enter a union by one's own decision and to leave the other person the same right. Not to hold anyone by deception, not to decide on a partner's behalf, and not to turn a family into a contract that only one side knows about.