Does Resenting Polygamy Take a Woman out of Islam?
Question

I read in the answer to question no. 31807  :  
“Whoever hates any part of that which the Prophet (peace and blessings of Allah be upon him) brought, even if he acts in accordance with it, is a disbeliever, because Allah says (interpretation of the meaning): 
{That is because they hate that which Allah has sent down (this Qur’an and Islamic laws); so He has made their deeds fruitless}
[Muhammad 47:9] …
With regard to all of these acts that nullify Islam, it makes no difference whether a person is joking, serious or afraid, unless he is forced to do it. All of them are very serious, and they all happen a great deal. The Muslim should beware of them and fear falling into them. We seek refuge with Allah from the things that may incur His wrath and painful punishment. May Allah send blessings and peace upon the best of His creation, Muhammad, and upon his family and companions.”
Many women resent polygamy and state that openly, either in jest or in earnest. Does this come under the heading of things that could lead to apostasy, and do they have to repent and do ghusl [to enter Islam again]?
Praise be to Allah.If the Muslim is content with the ruling of Allah and submits to it, and he does not reject it or object to it, this is what is required of him, and it will not matter whether he has a natural aversion towards it, such as the natural aversion to fighting a war, if he accepts it and submits to the ruling of Allah. Allah, may He be exalted, says (interpretation of the meaning):
{Fighting has been enjoined upon you while it is hateful to you. But perhaps you hate a thing and it is good for you; and perhaps you love a thing and it is bad for you. And Allah Knows, while you know not.} [Al-Baqarah 2:216]
An example of that is a woman’s disliking any competition. This is something natural, because a co-wife is going to compete with her over her husband. But there is a difference between resenting the fact that Allah has enjoined fighting and a natural aversion towards fighting, between resenting Allah’s prescription of polygamy and a natural aversion towards having a co-wife.
Whatever Allah has enjoined and prescribed , we must love it out of faith and to draw close to Him, even if one feels an aversion towards the action that has been enjoined and finds it difficult. However, the stronger a person’s faith grows, the more he will come to love these things to which he had felt this natural aversion, and he will begin to love them out of faith.
What was mentioned about the things that nullify Islam refers to resentment towards what Allah has sent down, and resentment towards what He has prescribed.
Ibn Al-Qayyim (may Allah have mercy on him) said: 
“It is not a condition of being content with what Allah has prescribed that one should not feel pain and hardship when doing it; rather the condition is that one should not object to the ruling or feel resentment towards it. Hence some people did not understand how someone could be content with that which he dislikes and feels a natural aversion to, and they criticised this idea by saying: This is not possible and is contrary to human nature; rather it is only patience (without contentment), otherwise how could contentment and resentment coexist, when they are opposites?
The correct view is that there is no contradiction between them, and feeling pain and natural aversion does not contradict contentment, just as one who is sick will be content to take unpleasant medicine, and one who is fasting will be content to fast on a hot day and undergo the pain of hunger and thirst, and the Mujahid will be content with what he faces of the pain of injury, and so on, in Allah’s cause." (Madarij As-Salikin  2/175).
Shaykh Ibn `Uthaymin (may Allah have mercy on him) said, explaining this matter: 
“Regarding the words of Allah {while it is hateful to you} [Al-Baqarah 2:216], the word Kurh [translated here as “it is hateful”] means it is disliked by you. 
The phrase {while it is hateful to you} refers to a state of mind. The pronoun “it” refers to fighting, not to the fact that it is enjoined, for the Muslims do not resent what Allah has enjoined upon them; rather their dislike of fighting is a natural, human aversion. There is a difference between saying, “We resent what Allah has enjoined of fighting” and saying, “We feel a natural aversion towards fighting.” Feeling an aversion towards fighting is something natural, for a person would dislike fighting someone and killing him, or being killed himself. But when this fighting is enjoined upon us by Allah, it becomes beloved to us in one way and disliked by us in another way. From the perspective that Allah has enjoined it upon us, we love it; hence the Companions (may Allah be pleased with them) would come to the Messenger (blessings and peace of Allah be upon him) and insist on joining the fight. But from the perspective that we have a natural aversion towards it, it is disliked by us.”
Then he (may Allah have mercy on him) noted one of the things we learn from the verse saying: 
“There is nothing wrong with a person disliking what is prescribed for him, not because the Lawgiver has prescribed it, but because of his natural aversion towards it. But from the perspective that the Lawgiver has enjoined it, then what we must do is be content and happy with it." (Tafsir Al-Qur’an by Ibn `Uthaymin).
Elsewhere, he (may Allah have mercy on him) said: 
“From the words {while it is hateful to you}, you should understand that the pronoun here refers to fighting, and does not refer to the fact that it is enjoined, because the Companions (may Allah be pleased with them) could not have resented what Allah enjoined; rather they disliked the idea of fighting and being killed. There is a difference between a person disliking the ruling of Allah and his disliking what is enjoined." (Mu’allafat Ash-Shaykh Ibn `Uthaymin  2/438)
In conclusion, the believing woman should be content with the fact that Allah has prescribed polygamy , and she should believe that there is wisdom in it and that it serves an interest. She should not resent this ruling , even if she has a natural aversion to the presence of a co-wife who competes with her, just as men dislike fighting. 
People may feel a natural aversion towards that which causes discomfort, such as doing Wudu with cold water for Fajr prayer, fasting in intense heat, and other things that involve hardship, but we should suppress these negative thoughts out of love for Allah, and we should be content with His ruling and submit to what He has prescribed. Hence it says in the Hadith which was narrated by Al-Bukhari (6487) and Muslim (2823) from Anas ibn Malik (may Allah be pleased with him) that the Messenger of Allah (blessings and peace of Allah be upon him) said: “Paradise is surrounded with hardships [which people dislike] and Hell is surrounded with desires [which people like].”
An-Nawawi (may Allah have mercy on him) said in Sharh Muslim: 
“As for the hardships, they include striving in doing acts of worship and persisting in that, bearing with patience the hardships involved therein, and suppressing rage, forgiving people, being forbearing, giving charity, showing kindness to the one who mistreats you, showing patience in resisting desires, and so on.”
Similar to that is the Hadith in which the Prophet (blessings and peace of Allah be upon him) said: “Shall I not tell you something by means of which Allah erases sins and raises people in status?” They said: Yes, O Messenger of Allah. He said: “Doing Wudu’ properly at times when it is difficult to do so, taking many steps to the mosque, and waiting for prayer after prayer. That is constant readiness.” (Narrated by Muslim, 9251, from Abu Hurayrah (may Allah be pleased with him))
An-Nawawi (may Allah have mercy on him) said: 
“The difficulties [involved in doing Wudu properly] include doing it when it is very cold or one is suffering physical pain, and so on.”
And Allah knows best.