The ruling on a couple who married and had children, then learned of their milk kinship

Question:
A man married a woman and had children with her, but he later learned that she was his sister through breastfeeding. What is the ruling on his marriage to her? And what about the children she bore from him? Please inform us, may Allah reward you with good.

Answer:
The children are his children, and the consideration is based on the apparent valid marriage contract. He bears no sin or blame in this matter if they did not fall short or neglect their duty, since they only learned that she was his sister through breastfeeding afterwards. This does not harm them. The children are his children, and they bear no sin as long as they did not know until afterwards. Praise be to Allah, and Allah (Exalted and Majestic is He) does not hold a person accountable for ignorance; rather, He holds a person accountable for what he intentionally does: [al-Baqarah:286]. If he did not intentionally commit falsehood, he owes nothing.
Q: He says: Should he divorce her?
A: The marriage is invalid... the marriage is invalid. If he learns that she is his sister, the marriage is invalid. However, if he divorces her with one divorce due to the doubt, he divorces her with one... if he divorces her with one divorce, that is more cautious; to avoid the difference of opinion. He should divorce her with one divorce so that it can be relied upon for her marriage to another.