What is the ruling on a husband remaining in his wife's room and spending the night there, despite the absence of any contact between them, his having divorced her multiple times, his ill-treatment of her, and his repeated insults to her? And what is she required to do, Islamically?

If a husband divorces his wife with less than three pronouncements and takes her back during her waiting period (iddah), she remains his wife, and she must obey him in what is good. She has the right to present any abuse to a judge. However, if the wife is certain that she has been divorced with three pronouncements, she is irrevocably divorced from him (baynunah kubra), and it is not permissible for her to allow him access to her. She must seek separation from him, even through khul (divorce at the wife's instance), and she must flee from him if she has no proof of the divorce other than her own certainty.