Albert Barnes Commentary 1 Kings 1:2

"Wherefore his servants said unto him, Let there be sought for my lord the king a young virgin: and let her stand before the king, and cherish him; and let her lie in thy bosom, that my lord the king may get heat." — 1 Kings 1:2 (ASV)

Since Jewish law allowed polygamy, David’s conduct in following what was reportedly a physician’s advice was blameless.