I've been wanting something like this forever. Idc if it is exactly as gildre described, but marriage was such a huge part of the medieval world, and had so many far-reaching applications, that NOT having it in a medieval sim is just a glaring omission.
IMO, there doesn't even need to be an IG mechanic other than an entry into family history and character pages that says Married or Spouse of <Link>. While it would be cool to have at least SOME IG effects, I'd be happy with just the above for starters.
