What is incumbent upon a man who married his sister through breastfeeding and had children with her, then learned the reality of their kinship?

A man must separate from his wife if it is proven that she is his sister through suckling, due to the Prophet's (peace be upon him) saying: "How can this be, when it has been said?!" and his saying: "Leave her." As for the children, they are attributed to their father because it is a marriage of شبهة (doubt/ شبهة contract).