What is the ruling of Islamic law regarding a husband who spends most of his time with his son from a previous non-Muslim wife, and stays overnight at her place, while neglecting his current wife who lives alone in a foreign land, has no children, and is not employed, and is the wife mistaken in demanding her rights?

If a woman is divorced, upon the completion of her iddah (waiting period), she becomes a stranger to her ex-husband. It is impermissible for him to stay overnight with her, or be in seclusion with her, or touch her. Furthermore, an ex-husband staying overnight with his disbelieving ex-wife is forbidden and a cause for temptation, so he must cease this immediately. The custody of a Muslim child by a disbelieving mother is a matter of dispute, and the preponderant opinion is that it is not permissible because it may expose the child to misguidance. The husband must strive to get his son back. The wife has rights over her husband, including kind treatment and spending time with her. The wife should be patient and gentle in conveying what she wishes to her husband and offering her readiness to care for his son.