The ruling on differentiating between the two wives in the use of contraceptives

The questioner, Umm Abdullah from Riyadh, says: A woman is complaining about her husband, as he is married to another woman. She says that he does not treat them equally, even though he is a committed person who performs the obligatory prayers at their times and is upright, and she praises Allah for that. He asks her not to use contraceptives, whereas he has left the second wife free to choose. What is your advice, Your Eminence the Shaykh, for them?
Answer: My advice to everyone is, first, that the husband should be just and fear Allah in this matter; because Allah has made it obligatory for him to be just between the two wives in terms of division of time and financial maintenance. He should not favor one of them over the other, but rather he must be just between them. As for his preventing this one from pregnancy by taking pills while not preventing the other, this may have a consideration for him for reasons that necessitate that, and this is a matter for consideration. If there are no reasons that necessitate that, then the obligatory thing is to allow both of them; because each one wants children. However, if the one who is prevented from having children would be harmed by pregnancy due to illness, it harms her... she has reasonable reasons, he is excused. But to prevent her from having children without reasons and allow the other, this contains a type of injustice.
So the obligatory thing is to allow both of them, and it is not permissible for either of them to prevent pregnancy, both of them. It is not permissible for him and it is not permissible for her. Rather, it is obligatory for both of them to strive in the causes of pregnancy; because the Messenger (peace and blessings be upon him) ordered to marry the fertile and loving woman and said: So what is required is to increase the offspring. It is prescribed for the husband and wife to strive to increase the offspring, and perhaps Allah will benefit them with that. Indeed, among the great blessings is that they are granted righteous offspring. So there is no basis for prevention, and there is no basis for agreeing on prevention either, except for a legal cause, for legal reasons that necessitate temporary prevention, such as if she is ill and pregnancy would harm her, or if she has an infant and pregnancy would harm him, or if pregnancy would harm her as well. The point is, if it is for legal reasons, there is no harm. But preventing this one without a legal reason, or this one without a legal reason, or preventing both without a legal reason, all of this is not permissible. Yes.
The presenter: May Allah reward you with good, Your Eminence.