This is for a 46 years man with two wives. One is one year older than him and the other is about 9 years younger. He is trying to be just to both the wives in all aspects and he is successful in majority of the cases. His problem is that he is not attracted to his first wife to perform sexual activities at all. However they love each so much and they get along very well. Is he committing any sin by not having sex with his first wife? He has tried a lot to be able to but without success.

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.

Being just with wives is an obligation upon the husband. Allah Says (interpretation of meaning): {…but if you fear that you shall not be able to deal justly (with them), then only one or (the captives and the slaves) that your right hands possess. That is nearer to prevent you from doing injustice.}[4:3]. The Prophet (Sallallahu Alaihi wa Sallam) said: "If a man has two wives and does not do justly with them, in The Here-after he will come with half his body fallen." The justice that is demanded in Shariah is in the matters of expenditure, accommodation, staying the night and similar material matters which are under the control of a person. As for having sex the husband is not required to do it equally since it depends on the natural desire. But it should not reach the extend that harms the wife. It is also not permissible for him to avoid having sex with a wife only to save his strength and enjoyment for the other one. We advise the brother to take precautions and means that arouse one's sexual desire such as wearing perfumes, beautifying oneself, mutual sexual stimulation prior to sexual intercourse, etc. If it does not work, it might be due to the influence of Jinn or magic. To get rid of this problem he has to recite verses from Qur'an and authentic supplications from Sunnah. He may even ask a religious person to recite Qur'an on him. However, one is not held accountable for the affection that one feels in his heart, which is out of his control. Even though he should not love only one wife so much that it could change his attitude towards the other wife. Allah Says (interpretation of meaning): {….so do not incline too much to one of them (by giving her more of your time and provision) so as to leave the other hanging (i.e. neither divorced nor married). …}[4:129]. The Prophet (Sallallahu Alaihi wa Sallam) used to deal justly with his wives and used to say: 'O Allah! It is my distribution in what I own, O Allah do not punish me for what only You own and I do not own.  Abu Dawood and said, 'He meant by "What only you own" the heart/the affection, the love.'

Allah knows best.