Advice for the First Wife
Question :
My wife was afflicted by a skin disease which has deformed all of her body, but it is not contagious; and the doctors agreed that there is no cure for it. Now I feel a great aversion to her, especially at the time of having sexual intercourse and I have given up hope of adjusting myself to her situation, so I have considered marriage. I sought her opinion in the matter and she flared up in anger and resolved to seek a divorce if I do so. What does the religion say to me and to her?
Answer:
As for you, I consider that there is no sin upon you if you marry a woman, because Allah has made it permissible for His worshippers that the man may marry four women, unless he fears that he will be unjust.
As for her, I advise her not to get angry at your thoughts of marriage, nor at your marriage, because this is something which Allah has made permissible for you and because you have an excuse in this situation. And the situation which has befallen her is a calamity over which she should be patient. She should ask Allah for forgiveness and it might be a cause of her sins being remitted and the raising of her status before Allah, Most High. And Allah knows best.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 5 Pages 356