What is the ruling on divorcing an atheist who swore to divorce many times in a fit of rage, then returned to Islam and remembered his oaths?

If the man is described as an apostate at the time of the marriage contract, then his contract is void due to the invalidity of a disbeliever marrying a Muslim woman. However, if the contract was made while he was a Muslim and then he apostatized, then his divorce before the apostasy is considered to have taken effect. After apostasy, if he repents and returns to Islam before the expiry of the iddah (waiting period), his divorce is considered to have taken effect. But if he does not repent until the iddah expires, then the marriage contract is considered nullified, and the divorce does not take effect during the iddah. Children born after the husband's apostasy and before his repentance are attributed to him due to the شبهة (doubt/semblance of legitimacy).