According to your doctrine polygamy would be wrong. But the Bible permitted it.

The Catholic Answers

Christ clearly tells us that, whatever concessions were made in the Old Law, it was God’s intention from the very beginning that a man should cleave to his wife, not to his wives, and that they should be two in one flesh. God had made concessions because of the hardness of men’s hearts in the less perfect Law, but those concessions were withdrawn in the more perfect Law. Christ restored the primitive law, and said, “Henceforth what God hath joined together, let not man put asunder.” Mk. X., 2-9.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty