Zombie thread alert! (Racks shotgun…)

I always wonder how threads come to life again after being buried in months and months of newer posts. Did you go searching for polygamy threads?
I encourage people to do more reading from reputable sources on the topic rather than just read their bibles and fill in the blanks with imagination (or more likely - rationalizations). There is a consistent history behind the catholic moral teaching on monogamy. Judaism had largely already learned the painful lesson of polygamy by the time of Christ. Polygamy was alive and well in the Greco-Roman world, but not so much among observant Jews. They had learned the hard lessons of the OT patriarchs.
In Matthew 19, Jesus lays out the fullness of what marriage is intended to be. He doesn’t discuss polygamy for the simple reason that the issue didn’t exist for Jews. They already understood its harmful nature, it didn’t need discussing. What Jesus DID explain was the way in which man and woman join together and become one flesh. That union images God himself in that it is able to produce new life. The idea of the man subsequently heading for the OTHER wing of his house the next night for his OTHER “one flesh” experience simply makes a mockery of Jesus’ point.
Salvation history is a process that took millenia. I’m a father myself. I have a 5 year old who has gone from a helpless infant to an amazing tiny personality with impressive abilities. As a parent, I’ve helped her grow and learn in many ways. She learns from mistakes and achievements. But as a parent, you take it as a process. You don’t nitpick to the point of being destructive, you build up and correct constructively. My 5 year old has always used “amen’t” verbally. (i.e. I amen’t hungry). It’s incorrect, but we haven’t corrected it yet. As she’s learning to read, that time has come. So it is in revelation. God revealed and made explicit truths as humanity became ready for them. Jesus gave us the fullness of what marriage is in Matthew 19. It’s not compatible with multiple wives.
Jesus elsewhere tells us that human marriage is foreshadowing of heavenly union with God and that our earthly marriages are for this world alone. This is why widows can remarry.
Contrary to a poster above, Jesus does not give permission to divorce and remarry. What he did was allow a “divorce” for those in a “marriage” which was really never any such thing due to a fundamental defect that prevented it from being a true marriage (porneia).
I must admit that I’ve heard the argument before that fornication was OK since the 10 commandements only prohibited “adultery.” Until now, I thought only teenage boys made that argument though…
As to Paul and the bishop “man of one wife” thing, it’s again a context issue. St. Paul is the guy who brought the gospel to the Gentiles. The Gentiles were the ones still practicing polygamy. Converts had some sticky issues to deal with. St. Paul decided that prudence required that converts that had previously been polygamists just shouldn’t be bishops. That prevented people from getting the wrong idea about the compatibility of christianity and polygamy (until fairly recent times, anyways!)
In the end, it’s not hard to understand why polygamy, fornication or divorce/remarriage are immoral once you understand what marriage was invented to be. It’s a lifelong union of a man and woman that involves so great a gift of self to the other that it’s very nature is ordered towards creating and nurturing new life. No behavior incompatible with that purpose of marriage can be tolerated.