What should a wife do if her husband persists in following a fatwa that permits anal sex, and is she allowed to seek a divorce?

Anal intercourse is undoubtedly forbidden and is a major sin. Some scholars have gone so far as to rule that a separation between spouses is obligatory if they agree to anal intercourse. The wife must make this clear to her husband, and if he insists on doing it, she is not permitted to obey him, even if it leads to divorce; for there is no obedience to a creature in disobedience to the Creator.