He divorced her officially and irrevocably, and now he wants to go back to her

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Check below answers in case you are looking for other related questions:
Tahleel marriage is haraam and invalid
If he says to his wife “Your bed is haraam for me”

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Related Answers:
He left the house and went away. Is this counted as a talaaq (divorce)?
If he says to his wife, “Divorce [talaaq]” or “You are divorce”
He said to his wife: If you go out you are divorced, and he previously divorced her twice (talaaq)
Tahleel marriage is haraam and invalid
If he says to his wife “Your bed is haraam for me”

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