Not everyone with several wives in the Bible had trouble. With Jacob there was some trouble, but overall I think he did pretty well. King David’s son Solomon came from Bat Sheva who was not David’s first or only wife. Caleb Ben Yefuna had a few wives and few girls friend simultaneously and the Bible says about him the most unique phrase it uses anywhere וימלא אחרי השם He walked totally with God. “Totally” here means “completely,” or 100%.
[Nature abhors a vacuum. I see this a lot. People don't like the Law of Moses so they make up their own prohibitions, and ignore things that are clearly forbidden in the Law of God.]
The general way to understand the Law of Moses is thus: There are things that are forbidden. These always come with the words, "Thou shalt not do such and such." There are things one must do. They always come with the words, "Thou shalt do such and such." Then there are things that are neither forbidden nor obligated. They might be good to do but they are not obligated. There might be things that are not prudent, but they are not forbidden.
Christians try to argue that two wives is not prudent and therefore must be forbidden. However that does not follow. Also the entire existence of the Jewish people is the result of Jacob having four wives. Plus Caleb Ben Yefuna is not a minor figure in the Bible. He is well known as the friend of Joshua and the fact that he had a few wives and girl friends is not ignoble.
I am simply trying to make a difference between what the Law of Moses forbids and that which it does not forbid. The cases of multiple wives that I know about are usually quite happy. The women are attached to some Alpha Male and are willing to put up with anything in order to be with him. And I never saw anything to indicate that the children were worse off. But people that are more familiar with Mormons might have different observations--I admit.
