Is there such a thing as a temporary mahram?

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Check below answers in case you are looking for other related questions:
Is it permissible for him to marry the daughter of his wife’s sister after she dies
If he marries a woman she becomes permanently forbidden in marriage to his father

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Related Answers:
She breastfed a child thinking that it was her son; is the mahram relationship through breastfeeding established?
If the custom is for a girl not to marry her cousin, does he become a mahram for her?
Attribution of an illegitimate child and rulings that result from that
Is it permissible for him to marry the daughter of his wife’s sister after she dies
If he marries a woman she becomes permanently forbidden in marriage to his father

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