Is there a legitimate way, other than divorce, to reunite a family that separated after an eight-year marriage, which was preceded by an illicit relationship and then the repentance of both spouses, in order to avoid the family's dispersal after they learned of the invalidity of the initial marriage contract?

If a man had an illicit relationship with a woman that did not reach the level of zina (fornication/adultery), and then he married her with a valid, Islamic marriage, it is permissible. If the relationship did involve zina, the majority of scholars hold that the marriage is valid even before repentance. The child born to them is their legitimate son, as long as he was born after the marriage contract and after six months had passed from the contract. They are not required to divorce. If he divorces her, he may take her back during her iddah (waiting period) without a new contract. If her iddah ends, he must draw up a new contract with her.