What should a woman do who hates her husband and has no desire for him, and is unable to fulfill his marital rights, and whose husband has married at her request, but she does not want a divorce because of the children?

A wife must fulfill her husband's marital rights unless she is harmed. It is not permissible for her to refuse simply due to a lack of desire. If she is harmed by remaining with him, she has the right to seek a divorce. If the husband marries a second wife, this might alleviate her resentment and distress, and her patience for the sake of her children would be better, and she would be rewarded for it. Both should strive to remove the estrangement through supplication and forgiving the wrongdoer, in accordance with the Almighty's saying: "Repel [evil] with that which is better; then will close [associate], you will see, that between whom and you was enmity become as though he was a devoted friend."