What should a wife do if her husband insists on engaging in unlawful intercourse with her (anal sex) and threatens to divorce her if she does not agree, telling her that these matters are secrets that should not leave the house, knowing that the wife has come to despise his closeness and prays to Allah that He does not unite her with him in the Hereafter?

It is not permissible to have anal sex with one's wife, as it is forbidden and considered a major sin. This is based on the Prophet's (peace be upon him) sayings: "Cursed is he who has intercourse with a woman in her anus," and "Allah will not look at a man who has intercourse with another man or a woman in her anus." Therefore, it is not permissible to obey the husband in this request, as it is an act of disobedience to Allah. The wife must advise her husband, and if he does not desist, she has the right to seek divorce from him.