The ruling on one who commits unlawful sexual intercourse with a woman, then she becomes pregnant, and he marries her afterward

Question:
A questioner says: A man married a woman without a marriage contract and without any witnesses, after he had confirmed that she was three months pregnant. He then performed the marriage contract, and she gave birth. Then she became pregnant for the second time, and while she was pregnant, he divorced her with one pronouncement of divorce. Then, after a week, he divorced her with three pronouncements. He asked a man who is not a scholar, and the man told him: "You have nothing to worry about; continue with your wife." So what is the status of the first child? And what is the ruling on her divorce with three pronouncements? After the triple divorce, the marital life continued, and she now has three children with him?

Answer:
If his initial act was without a contract, may Allah protect us from it, it is explicit unlawful sexual intercourse (zina). The child from zina is not attributed to the fornicator but follows the woman. He is subject to the prescribed legal punishment for zina: if he is a married man, he is stoned to death; if he is a virgin, he is flogged one hundred times and exiled for one year. He must refer to the court in his country so that they can explain to him and inform him of what is required of him.
We ask Allah for guidance for us and for him.