Actually, the Bible records multiple wives, but it never supports it. David is warned not to accumulate wives or horses and Solomon pays a high price for accumulating wives. There are few other mentions of polygamy, but they are only mentioned, never condoned.
The definition of marriage as given in Genesis is one man and one woman. Jesus reaffirmed that definition as did Paul.
One can only justify polygamy via the Bible by ignoring much of the Bible. That is generally a bad way to read the Bible.
Shalom.
Excellent point ArGee. I was thinking how David was a man after God's own heart and yet had many wives. I guess that falls into God's permitting rather than approving.