As an outsider looking in, I find it strange that so many are struggling with separating sexual preferences from the duty to procreate.
This isn't even just about gay people; for thousands of years, humanity had men and women who reproduce with each other due to obligation, while feeling no love with each other. This had been the historical NORM. Everyone did this, everywhere, through out time.
If anything, many ancient cultures have openly gay people who married and have children anyway, and at no point did historians single them out for being unusual.
The cultural whiplash here, is that too many people today got used to the idea of not having children, when that was unacceptable even not that long ago. And never mind the idea of marrying someone you don't love.
The game was being ironically historically accurate, its just that the reality stings. Have as many lovers of any gender you want, but you still need a legit heir at some point. Secure the heir, and you are free to go off and love anyone you want afterwards.
Historical accuracy.
Have you played the game? there's a shit ton of Deus Ex Machina involved to get around this, or just don't. People without descendants have existed since the start of times.
At the end though, the problem isn't simply that they did X or Y, is that they lied to par to their fanbase, the ones that are represented in like 1% at most on videogames and this being one of the very few games where they finally got represented.