Let me address those in reverse order.
And limit each char to one living spouse (but what of the harem roleplays?).
You may be pleased to note that I never said marriage would be limited to one spouse, I only said that it was till death do you part. I can think of at least two major medieval cultures that sported polygamy, although they were not necessarily European. So you go do you Vita you scandalous dog you.
, which, if accepted, would add an entry to both their family histories as having married the other?
yup
(hohoho, are we gonna tackle same-sex marriages in BM too?)
I mean, its not period, but it neither is the Beppo, female captains, or warrior queens. Let's do it.
So, strictly mechanically, you're asking for a feature to propose a marriage to someone in-region
Basically, although making it a function of he priest is more fancy AND more period.
I think you're skimping on summary and description a bit, and getting carried away with arguing for the feature 
You wound me. You're not wrong, per say, but truth hurts.
Logged
"Behavior that's admired is the path to power among people everywhere"
