Lifespan of wives

In my current game as the Norse in the Britannia campaign, I married my 20-year-old faction heir to a lovely 35-year-old Welsh princess (she had at least 5 hearts). They started churning out kids and I realized that i've never had a marriage in this game where the wife was so much older than the husband. Marrying your 40-year-old king to a comely 16-year-old princess is common, but i've never really seen the reverse. Will the older wife stop being fertile some time in the future, say, around age 50? Is it possible for her to die before her husband, and if so, can he remarry?

I've had wives bear children at the age of 55 and thus dont think wives ever become infertile. The "past childbearing age" event is only a limit on when princesses can be married off.

He cannot remarry, and if they both die of old age she'll die first, but it doesn't matter once she pops out all her kids.

:egypt:

She can only have 4 kids so if they have been 'churning out kids' they are might already be at the max.