Thankfully, we don't abide by the world's culture, but by God's culture. In the New Testament it says one wife. When God made man and said that man should be alone, God didn't create multiple women for him (wives), but one woman (wife), Eve. I think by that statement alone we know what God prefers. Adam didn't have multiple wives, did he? Nope. It was only when the chosen people became influenced by the world's culture that they took multiple wives.
Plus, out of all the histories in the Bible, we only have a handful that had many wives. We must remember that these men were human and made choices based on their flesh, just like we do, and we shouldn't assume that because they had many wives, God was okay with it. I don't believe the Bible ever says "God is okay with many wives" or polygamy would be legal, right?
Quote taken from: Here's the Plain Truth About OLD TESTAMENT POLYGAMY
Plus, out of all the histories in the Bible, we only have a handful that had many wives. We must remember that these men were human and made choices based on their flesh, just like we do, and we shouldn't assume that because they had many wives, God was okay with it. I don't believe the Bible ever says "God is okay with many wives" or polygamy would be legal, right?
Quote taken from: Here's the Plain Truth About OLD TESTAMENT POLYGAMY
The only thing that changes in the Bible in terms of the acceptability of Polygamy is the culture of the Geographic region. Remember that the OT and NT are (mostly) books from different parts of the world.