Does divorce occur if the husband says, "If you return to this subject, then you are divorced," and the wife returns to the mentioned subject?

If you conditioned your wife's divorce upon an event and it occurred, and you were angry at the time of conditioning, refer to Fatwa No. 31893 to determine whether the divorce has taken place or not.

As for what you should have done, it was to take your wife back. The method of taking her back is mentioned in the previous fatwa.

As for what is obligatory upon you now: if her waiting period (iddah) has not expired, take her back. If it has expired without you taking her back, then you cannot take her back except with a new marriage contract. The waiting period (iddah) expires after three menstrual cycles, or by delivering the baby if she is pregnant, or after three months if she has despaired of menstruation due to old age.