A good relationship between the spouses means that each of them should pay attention to the feelings of the other and they should try to make one another happy. It also means paying attention to the spouse's circumstances and relationship with those who have right over him or her, so as to help him fulfil those rights, such as the rights of parents, relatives, neighbours and so on. The basis for all of that is understanding, love and compassion.
The sister who asked this question should be careful in evaluating matters. Her husband's sitting with his sisters on some occasions may be acceptable, because he sees them only rarely or they may need to ask him about something or they may have a problem, and the like. If there is no justification for it and the real reason is the husband's not being aware of the consequences of his actions and his neglecting her rights, then she has to deal with this situation properly so as to lessen its impact and not to make matters worse. The wife is the one who knows what will affect her husband, what he likes and what he dislikes. In general terms we may tell this sister that treating the husband kindly and overlooking his bad treatment or responding to it with good treatment is what will bring hearts together and replace loneliness with comfort and love. Our Lord, the All-Knowing, All-Aware, says (interpretation of the meaning):
The good deed and the evil deed cannot be equal. Repel (the evil) with one which is better (i.e. Allah ordered the faithful believers to be patient at the time of anger, and to excuse those who treat them badly), then verily! he, between whom and you there was enmity, (will become) as though he was a close friend.
But none is granted it (the above quality) except those who are patient, and none is granted it except the owner of the great portion (of the happiness in the Hereafter i.e. Paradise and in this world of a high moral character)
As-Sadi said in Tayseer al-Kareem al-Rahmaan (p. 749):
Then Allah enjoins showing a special type of kindness that will have a great impact, which is treating kindly the one who mistreats you. Allah says, Repel (the evil) with one which is better i.e., if someone mistreats you, especially if he has significant rights over you, such as relatives, friends and so on, in word or deed, then respond in a way that is better. If he severs ties with you, uphold ties with him; if he wrongs you, forgive him; if he talks about you behind your back or in your presence, do not respond in kind - rather forgive him and speak to him gently; if he shuns you and does not speak to you, then speak to him kindly and greet him with salaam. If you respond to mistreatment with kindness you will attain great benefits.
then verily! he, between whom and you there was enmity, (will become) as though he was a close friend i.e., as if he is near and dear
But none is granted it i.e., no one is granted this praiseworthy quality
except those who are patient in putting up with what they dislike and respond to it in the way that Allah likes, for people are naturally inclined to respond to bad treatment with more bad treatment, and not to forgive it. So how about responding with kind treatment. If a person is patient, obeys the command of his Lord, is aware of the great reward, and knows that responding to bad treatment in kind will not benefit him in any way and will only make the enmity stronger, whereas treating him kindly will not lower his esteem and that in fact the one who is humble for the sake of Allah, He will raise him in status -- then it will be easy for him and he will find joy in doing that.
and none is granted it except the owner of the great portion (of happiness in the Hereafter i.e. Paradise, and in this world of a high moral character) because it is one of the attributes of the elite among mankind, by means of which a person attains high status in this world and in the Hereafter, which is the greatest of noble characteristics. End quote.
It was narrated that Uqbah ibn Aamir said: I met the Messenger of Allah (blessings and peace of Allah be upon him), and I took him by the hand and said: O Messenger of Allah, tell me of the most virtuous deeds. He said: O Uqbah, uphold ties with those who cut you off, give to those who withhold from you and turn away from those who mistreat you.
Narrated by Ahmad, 16883; classed as saheeh by al-Albaani in Saheeh at-Targheeb, 2536
This moral principle in interacting with others will help the sister in her relationship with her husband's mother and other relatives and acquaintances.
Interference of relatives and others in a couple's life in ways that spoil it and cause trouble is not acceptable according to shareeah and people's customs. This matter has to be dealt with wisely and carefully, so as to reduce negative consequences and achieve that which is in everyone's best interests. The basis for that is achieving mutual understanding and cooperation between the spouses in dealing with it. It may sometimes need patience. So long as the matter has nothing to do with halaal and haraam, as in the examples mentioned by the questioner of her husband's mother asking her to give her the cost of the udhiyah so that she can offer it on her behalf, it may be appropriate to respond to such requests if she can afford it, whilst indicating in an appropriate manner that she would like to do that for herself in coming years.
And Allah knows best.
Reproduced from Islam QA