All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the situation is as mentioned in the question, that this husband had divorced his wife three divorces at three different sessions and he took her back after every divorce, then, in this case, divorce takes place three times, and there is an agreement among the scholars about this. Also, if he had divorced her and (after a while) he divorced her again before he took her back, then she becomes irrevocably divorced from him as well according to the view of the majority of the jurists .
Therefore, this wife becomes irrevocably divorced from her husband and she becomes unlawful for him unless she marries another man a true marriage and he consummates the marriage with her and then he divorces her or dies. For more benefit, please refer to Fataawa 135765 and 82541.
However, Ibn Taymiyyah has a different opinion. He is of the view that the second divorce that one issues before having taken his wife back is null, in which case, the wife here is only divorced once and her husband may take her back before her waiting period finishes.
In any case, if this husband uttered divorce to his wife while intending to initiate divorce by uttering it while not knowing the consequences of this, then this does not prevent divorce from taking place as we clarified in Fatwa 92352.
Finally, it should be noted that both spouses should endeavor to achieve what maintains family stability, and the husband should avoid uttering the words of divorce as a solution to the problems that might occur otherwise there would be unpleasant consequences.
Allaah Knows best.