Is he sinning if he keeps one of his wives with him and sends the other back to his homeland?

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Check below answers in case you are looking for other related questions:
If his wife does not agree to him being away for more than six months
Ruling on plural marriage and conditions thereof

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Related Answers:
He is away from his country and his wife and he wants to take a second wife
He regrets his first marriage and wants to take a second wife
She wants to marry a man but the law does not permit plural marriage. What should she do?
If his wife does not agree to him being away for more than six months
Ruling on plural marriage and conditions thereof

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