Ummm… but what about all the men in the bible with many wives. There was no one man one wife thing in almost the entire Bible. Almost all of the people who are touted to be amazing examples of God’s peopel… were polygamists… and since that wasn’t enough, they would have the concubines on the side. Point that out and they run away.

There's several points in the Gospel where Christ points at a departure from this though, right, like in Matthew 19 and Matthew 22, but the most poignant passage is 1 Corinthians 7:

2 But since sexual immorality is occurring, each man should have sexual relations with his own wife, and each woman with her own husband. 3 The husband should fulfill his marital duty to his wife, and likewise the wife to her husband. 4 The wife does not have authority over her own body but yields it to her husband. In the same way, the husband does not have authority over his own body but yields it to his wife. 5 Do not deprive each other except perhaps by mutual consent and for a time, so that you may devote yourselves to prayer. Then come together again so that Satan will not tempt you because of your lack of self-control. 6 I say this as a concession, not as a command. 7 I wish that all of you were as I am. But each of you has your own gift from God; one has this gift, another has that.

8 Now to the unmarried[a] and the widows I say: It is good for them to stay unmarried, as I do. 9 But if they cannot control themselves, they should marry, for it is better to marry than to burn with passion.

The purpose of getting married is the relief of sexual lust - and since we are talking about just relieving it, the idea of having multiple wives or concubines on the side is a perversion of this. We can even look at the story of King David and Bathsheba as an example of why you shouldn't covet moaaarr wamen. It has been pointed out before that, like, adultery and lust are so powerful and pertinent that 2 of the 10 commandments are about it...

So i would say that one of the clarifications that exist, and one of the new usherings in of Christianity, is strict monogamy, and also praise for monasticism...