Josephus mentions Herod's polygamous marriages.
Josephus, Antiquities 17.1.3, in William Whiston, trans., The Works of Flavius Josephus, accessed June 5, 2023
Now Herod 1 the king had at this time nine wives; one of them Antipater's mother, and another the high priest's daughter, by whom he had a son of his own name. He had also one who was his brother's daughter, and another his sister's daughter; which two had no children. One of his wives also was of the Samaritan nation, whose sons were Antipas and Archelaus, and whose daughter was Olympias; which daughter was afterward married to Joseph, the king's brother's son; but Archelaus and Antipas were brought up with a certain private man at Rome. Herod had also to wife Cleopatra of Jerusalem, and by her he had his sons Herod and Philip; which last was also brought up at Rome. Pallas also was one of his wives, which bare him his son Phasaelus. And besides these, he had for his wives Phedra and E1pis, by whom he had his daughters Roxana and Salome. As for his elder daughters by the same mother with Alexander and Aristobulus, and whom Pheroras neglected to marry, he gave the one in marriage to Antipater, the king's sister's son, and the other to Phasaelus, his brother's son. And this was the posterity of Herod.
1 Those who have a mind to know all the family and descendants of Antipater the Idumean, and of Herod the Great, his son, and have a memory to preserve them all distinctly, may consult Josephus, Antiq. B. XVIII. ch. 5. sect. 4; and Of the War, B. I. ch. 28. sect. 4; in Havercamp's edition, p. 336; and Spanheim, lb. p. 402--405; and Reland, Paleslin. Part I. p. 178, 176.