I think you're skimping on summary and description a bit, and getting carried away with arguing for the feature
So, strictly mechanically, you're asking for a feature to propose a marriage to someone in-region (hohoho, are we gonna tackle same-sex marriages in BM too?), which, if accepted, would add an entry to both their family histories as having married the other? And limit each char to one living spouse (but what of the harem roleplays?).
