How can one do it in an act of worship? Why, it would be a sign of weakness that a man does not do this. He can indeed not do this, he can only become weak through it. Rather, it is due to his having committed a sin and that this sin has become a part of his soul, as is mentioned in Al-Qurtubi, Sharh Ishaq, p. 20. He does not mean that he is not allowed to have sexual intercourse with his wife but he is obliged to do this because his wife is his mujtahid. He is obliged to do it because she is his wife and it was obligatory upon him to marry her. 
Thus, if you are forced to be married to someone you do not want to marry, it is haram for you.
If you marry someone and you want to divorce them but they have married you in good faith, you need to give them a few days’ warning in writing and that in writing should state the reason you are divorcing for. You need to put a note that says: “I am divorcing you on account of your having committed an action of adultery.” This is what the Messenger of Allah (Allah bless him and give him peace) asked for his wives after he divorced them for adultery. You should not do it except after receiving the warning and this is the best way. If they fail to give you a warning notice, ask for divorce in writing and leave them in peace.
You can divorce a person if you feel he has sinned and you have a strong case for the case before the legal proceedings or if you deem that he is committing a sin. In the most difficult case, such as the case of a minor who has committed adultery, you can divorce him for good if you think he has made a mistake. 
Ibn ‘Abbas said: “If the husband is guilty of taking intercourse with his wife against her will, and if he was only defending herself against some aggressor, he is innocent of sin [so] it is not permitted for him to take her back in this state.” 
Some scholars explained this saying about a man and a woman’s marriage on marriage as being something that should be performed as soon as possible so that their marriage will not be a burden and become difficult to bring about. They say that a divorce does not take precedence over a marriage 
Ibn `Abbas said