Why do you say that if wife/husband is ill or one went far away for a few days then masturbation by either of them in the absence of the other is an illegal sexual act? There is no fornication here. Moreover, masturbation relieves him of sexual tension and prevents him from fornication. Hope you will answer this question. Thank you.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Masturbation is forbidden by the book of Allah.

Allah says: "; And those who guard their chastity (i.e. private parts, from illegal sexual acts. Except from their wives or (the captives and slaves) that their right hands possess, for then, they are free from blame; But whoever seeks beyond that, then those are the transgressors(Al-Mu'minun 23:5-7)

So Allah described those who resort to satisfying their desires with other than their wives and who their right hand possesses to be amongst the transgressors.

The Prophet (Sallallahu Alaihi wa Sallam) also said: "O, young people, whoever among you can marry, should marry, and whoever is unable to marry, should fast, as fasting diminishes his sexual power."

So, he described the ways of controlling one's desires by getting married or fasting. Therefore, masturbation is forbidden, because if there was third method in curing these desires, the Prophet (Sallallahu Alaihi wa Sallam) would have informed us about it.

In addition to this, masturbation causes other great harms. First, it weakens the body. Second, it causes depression (sorrow). Third, it could lead the person to commit fornication or adultery, and last many men have become sexually impotent because of it.

Sheikh Hussain Makhlouf, a former mufti of Egypt, gave a very good fatwa saying: "therefore, most of the people of knowledge are of the view that masturbation with one's hand is Haram. What strengthens this view is that masturbation causes major nervous, physical and mental harms, and this implies that it is forbidden."

Moreover, it is not permissible for a husband to be absent from his wife more than 6 months without a valid reason.

Ibn Qudama said in Al-Mughni: "Ahmed was asked: how long can a man be absent from his wife:? He replied: "It is narrated that he will be given a period of 6 months, but he can be absent for more than 6 months for a necessary matter". However, if he is absent more than that without excuse, then the people of our school of thought say that the judge will write to him, and if he refuses to comeback, then this marriage is nullified."

Nevertheless, if  a person is overwhelmed by his desires to an extent that he cannot curb them except by masturbation, or by committing fornication or adultery, then without any doubt committing the lesser of the two evils, which is masturbation, is less serious than committing the major sin, but this does not mean that masturbation is permissible.

As for saying that masturbation is a way of relief for the person, this is addressed above.

Therefore one should not let a temporary and momentary desire cause him/her to be punished and tortured in the hereafter.

Allah knows best.