I friend is having a serious problem. Please respond in detail. The issue is she is getting married in few days and her husband-to-be has given her hints that he is interested in having sex with her in an unnatural way (from behind). Kindly advise how she can dissuade him from this.
Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Having sex with one's wife in the anus is a great and major sin. This is forbidden in Shariah. And the natural disposition of human beings rejects it.
The Prophet (Sallallahu Alaihi wa Sallam) said: "Accursed is the one who has anal intercourse with his wife", (reported by Imam Ahmed).
Now this woman has to inform him that this matter is forbidden if there is no marriage contract yet between them. If she knows that this man is insisting on doing that matter after the marriage contract, she has to inform her guardian to nullify this marriage without informing him about the reason in order to conceal this man unless he insists on knowing the reason. Some Fuqaha state that if the husband has anal intercourse with the consent of his wife and they do not end that practice, then divorce has to take place between them.
It is also a fact that it is not permissible for the fiancé to be in seclusion with the fiancée, or to talk to her except for a necessity, and in the presence of one of her Mahrams.
And it is absolutely forbidden for him to discuss the matter mentioned in the question.
Please refer to Fatwa:86457.
Allah knows best.
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