Assalammualaikum, bdsm is a foreplay where a couple (husband and wife) enjoying private time together by tie up his/her couple and spank etc. The question is, is it permissible in Islam? if a man praticing this kind of fetishism, and likening his wife as slave, isn't that considered as dzihar?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

We have already issued Fatwa 84211 clarifying that such conduct (sadism) is a conduct that is contradictory to the morals of Islam in regard to having good marital relations between the spouses. So, sadism is not permissible as it causes harm and pain to the other spouse. In addition to this, this matter came to the Muslims from the other (non-Muslim) nations.

On the other hand, a husband considering his wife as his slave while practicing sadism upon her or in other cases is not considered as Thihaar. The definition of Thihaar according to the jurists is when a husband makes his wife or part of her like a woman who is permanently forbidden to him, like him saying to her: “You are like my mother to me”, meaning “You are (sexually) forbidden to me exactly like my mother.” For more benefit, please refer to Fataawa 85470 and 85975.

Allaah Knows best.