Why not enable the " recruitment " of several wives, anyway ?
We are trying to build our own clan, after all.
It would be appropriately immersive re the evident Aserai and Khuzait cultures, at least.
How would such a feature impact your game ? Some might enjoy playing this card, others might prefer the sole wife ( Vlandian? ) model.
It could not be a worse "exploit" than swinging a menavlion from the saddle, cavalry baseball - style ( " Mount and Bat ", anyone ? ).
And as for mistresses, and their bastards ..........
So, why not ? ( Too much work, and not core, I guess. Wait for a mod ........ ).