Is it permissible, in Islamic law, for a husband to beat and torture his wife to practice sadism based on his desire and their agreement, knowing that she sustains wounds and bruises and is commanded to show blind obedience and play the role of a slave, and she does this unwillingly to please him?

It is forbidden to beat or harm one's wife without a legitimate religious reason, such as insubordination (nushooz), because it is an aggression and an injustice. Allah has forbidden injustice for Himself and made it forbidden among His servants. This kind of beating contradicts living together amicably. The husband must fear Allah concerning his wife and treat her kindly, for the perfection of the marital relationship is achieved through affection and grace, not through actions that contradict Sharia and human nature.