My friend and I differ in our opinions about "cheating" spouses. Could you please clarify, if his view is the more Islaamicly correct one or whether mine is? I believe that when a married woman commits adultery it is a crime against Allaah and also her husband since he has rights to sexual exclusivity from his wife. Actually it is the only right he has from a woman, since she does not have any obligation to her husband except to have sex with him and be faithful to him. If his wife does commit adultery, he is entitled even recommended to divorce her. Therefore it is correct to say that the wife was "cheating" her husband.
Now, when the husband commits adultery, he isn't "cheating" his wife, since it is a crime against Allaah only. Of course, I accept the gravity of the situation, and in both cases it is a Kabeerah, however in the case of the husband he is not "cheating" his wife, since a wife's rights in Islam do not include sexual exclusivity. They include, food, drink, a home, and that he looks after her and treat her kindly albeit strictly if he sees fit. Her rights do not include her husband being faithful to her. Hence, it is incorrect to say that a man is "cheating" his wife if he does commit adultery. However, my friend insists that it works both ways. His opinion is that a husband can only have sex with his wife or slaves. Therefore if he does have sex with another woman, the crime is exactly the same i.e. He believes that a man is "cheating" his wife, if he commits adultery.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

First you have to know that the term cheating within marriage is not used in Islamic Law. If cheating means adultery, then this applies to whoever commits it whether the wife or the husband. However, if cheating means that one spouse is neglecting the rights of the other if he/she commits adultery, then the wife differs from the husband in this matter. If a wife commits adultery, she may conceive a child from the person she committed adultery with, and claim it to her husband which causes many harms in this world and in the Hereafter. The case is different if the husband commits adultery, the child cannot be claimed to be from his wife. Saying that the rights of the husband on his wife are in sexual exclusivity only is not correct, because she also has to obey him within what is permissible and so on. The statement of your friend that the husband can have sex with his wife and his slave-girl only and not with a woman he is not allowed to have sex with is correct, but it does not necessarily mean that he is neglectful about the rights of his wife by committing adultery. Anyway, adultery is one of the great major sins and an obnoxious act, that is why whoever commits such a sin deserves to be stoned to death whether it is the husband or the wife.

Allaah knows best.