Question 9: I want to marry to be able to perfect my faith but I feel I am unable to have sexual intercourse properly; what is your advice?
Answer: We advise you to marry so that Allaah might help you do it. If you manage to do it after marriage, it will be alright. Otherwise, you will have to divorce your wife unless she approves of living with you as such. However, if you know that you are totally impotent, you have to tell your fiancée about it, which if she accepts will be alright. Otherwise, you are not allowed to deceive her… read more here.