I'd been wanting something like this for a while. The idea I had was more about resetting diplomatic relations every era though, this is more interesting and involved, nice mod.

A few suggestions for options that could be added:
-Instead of Declarations of Friendship, make it so Defensive Pacts are counted as Marriages.
-Make it so Rulers only die naturally when the civilization enters a new Era.
-Change succession wars so that instead of actual war, some cities convert peacefully to the control of Marriage partners.

@Lifted to Heaven I'll look into it, thanks for the feedback.

This mod makes turn times much longer than before even in the ancient era. I think it need to be more streamlined.

Another brilliant stuff turns up!

Fabulous!