It might be harmful to your wife. That is why wisdom and discretion are needed.At least FiveSolas made a concerted effort to respond to the meatier posts. His last straw that he is clutching tight to, is the Matt 19:9. He knows he has got nothing left! Destroy that argument, and the only other thing he can hold onto, is this "harmful to your wife" claim.
That isn't the point of discussion. We are asserting that polygyny is lawful marriage in the sight of God. He is asserting that it isn't.