"You're either heartless or a polygamous jerk yourself if you can't see that."
From a guy's POV, too, how could you possibly have the same sort of intimacy that you have with one wife and six kids if you have six wives and 36 kids?
Somebody has to be getting the short stick in that arrangement.
And six mothers in law?
Polygamy can be a practical necessity if war or disease has left a society with a large surplus of women, particularly if it's a primitive society and the surplus women need someone to protect and feed them.
But that's a case of half a loaf being better than none, not an optimal situation.