1 Kings 11:3 records that among Solomon's women were 700 princesses and 300 concubines. A close reading of the Hebrew indicates that this verse is merely recording the number of foreign wives and concubines, not the total number of his women, which means that he had many more wives than this. The focus of the passage is on the women who worshiped gods other than YHWH and Solomon's building of high places and altars to those gods, which begs the question, what happened to Solomon? He was raised to be a good Jewish boy, and good Jewish boys don't marry shiksas, let alone 1000 of them. Seriously. Was the sex that good?
Our two cents: Solomon had mommy and daddy issues.
Read through 1 Kings chapter 1. This part of the "succession narrative" shows that David had no intention of making Solomon king until Bathsheba and Nathan got involved. Taking her cue from the story of Rebekah and Jacob screwing Esau out of his birthright, Bathsheba makes sure her little boy gets the crown by twisting the reality of a frail, old man who can't stay warm even with a beautiful young co-ed wrapped around his body.
Solomon had to live with this knowledge and the fact that his head never quite fully exited Bathsheba's womb; that it was her maternal manipulation that got him the throne, not the divine anointing his father received — attention from on high even Saul was allowed.
Because Solomon's kingdom begins with barely concealed deceit, there were immediate repercussions in the kingdom: an eminent civil war between those who have aligned themselves behind the rightful king (Adonijah, the eldest brother). A war is avoided because Solomon exiles or executes everyone who would stand against him; however, one should not miss that the text records Bathsheba's role in Adonijah's death.
Yes, Solomon built the Temple and centralized worship for the United Monarchy, but he did so on the backs of his people. The Hebrew text describes Solomon's actions in the same ways it does the Pharaoh who stood against Moses and Aaron. Solomon amassed wealth while enslaving his own people, creating Egyptian-like conditions in Israel. And while Solomon built one Temple to YHWH, he built countless more altars to "Astarte the goddess of the Sidonians, and Milcom the abomination of the Ammonites, and "built a high place for Chemosh the abomination of Moab, and for Molech the abomination of the Ammonites ... did the same for all his foreign wives, who offered incense and sacrificed to their gods." (1 Kings 11:4-8) And who physically built those altars? The enslaved people of Israel.
If we believe the sages of tradition, Solomon spent the rest of his life gathering wisdom and wine, whores and wives, vanities upon vanities. In the end his kingdom is divided and his legacy is the punch-line/by-word of the Deuteronomist's warning against kings. (c.f. Deuteronomy 17:14-20)
Perhaps this is part of the reason the book of Ecclesiastes is attributed to him: a book of wisdom and regret after a life ill-spent.
Perhaps he knew of his moral downfall and needed something to keep his mind off of his troubles. Something to keep him warm at night.
Perhaps this is why Solomon needed so many wives and concubines.
Perhaps the king had 99 problems and ...
But what do we know: we made this game and you probably think we're going to hell.