It's not just you. I have this same exact bug. I theorize, though I don't know for sure, that it's crashing because you're about to have a kid. I've gotten married every time, and it's always a little while after the marriage.
Actually, after getting married, it will take at least 40 turns before you give birth to your first child, more if you are particularly unlucky that game. It is also set so that you will not get married until at least 50 turns after the game has started. These are just placeholder times to make sure that the events are considered "special," so you don't end up with dozens of child heroes running around about the time you finally research some good equipment for your designed units. I think that, in the future, marriage will actually be quest-driven, and there will be ways to provide a bonus towards getting kids more quickly.
Question for the developers, if any are paying attention to this thread: Do any members of an army associated with a sovereign gain experience from battles, even a descendant, or is the sovereign the only one who gains experience?
The way it is right now, only heroes get experience from a battle, while your trained units just send their experience on to the sovereign. However, being that your kids ARE heroes, they should be getting experience...so it looks like you found a bug there . We'll look into fixing that.