The custody is with the mother as long as she does not remarry. Kindly refer to the following link(s): https://www.youtube.com/watch?v=U5GK8Wk9LFE&app=desktop

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If the father doesn’t object and the new husband is ok with that, this is permissible.

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Yes, the custody goes to the father unless he allows his ex to have the children and the new husband agrees to that.

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