Is it advisable to be patient with a wife in whom the husband no longer sees the beauty he saw before marriage, despite his Istikhara (prayer for guidance) and her commitment to religion and good character, especially with his mother's apparent disapproval of her; or should he separate from her, particularly given his fear of regretting the divorce later and the difficulty of telling his wife the reason?

One should accustom oneself to the wife and ask her to adorn herself for the husband, as Ibn Abbas, may Allah be pleased with him, said: "Indeed, I love to adorn myself for my wife just as I love for her to adorn herself for me, because Allah Almighty says: {And they (women) have rights similar to those (of men) over them in a just manner} [Quran 2:228]." A righteous wife is the best treasure a person can have, as she delights him when he looks at her due to her beauty and good conduct. Divorce is permissible but disliked unless there is a need for it, and the default is prohibition due to the negative consequences that result from it. As long as you have sought Allah's guidance through istikharah regarding your marriage to her, then there is good for you in that. Among the benefits of marriage is righteous offspring who are a comfort to the eye. As for the wife's relationship with the husband's mother, its being limited is normal and can be developed with wisdom.