When David returned to his palace in Jerusalem, he took the ten concubines he had left to care for the palace, and he placed them in a house under guard. He provided for them, but he no longer slept with them. They were confined until the day of their death, living as widows.
Jewish Publication Society of America Version (JPS1917) - 2 Samuel 20:3 >And David came to his house at Jerusalem; and the king took the ten women his concubines, whom he had left to keep the house, and put them in ward, and provided them with sustenance, but went not in unto them. So they were shut up unto the day of their death, in widowhood, with their husband alive.