How can one be saved from falling into immorality and addiction to it, and repent to Allah, if the wife withholds marital rights, including intercourse?

A wife is not permitted to refuse her husband's bed without a legitimate Shari excuse; otherwise, she deserves the curse of the angels. As for the husband's engagement in zina (fornication/adultery), it is a major sin and a great transgression, and he must repent immediately by cutting off his relationship with that woman. If his wife does not come to her senses, then he should marry another, while seeking assistance from what counteracts lust and avoiding provocations.