His First Wife is Disobedient

Question :

I am married to two women: One of them respects me, complies with my requests and obeys me; and she loves my children from the other wife and likewise my father and my family. As for the other one, she is completely opposite to the first in everything; is it permissible for me to be estranged from her or to avoid her?

Answer:

This wife who obeys you and honors your family and your children from another woman, is rewarded and deserving of praise. As for the other wife, who is opposite to that, she is a sinner, unless there is any reason for her disobedience. And Allah says in His Noble Book:
"As to those women on whose part you see ill conduct, admonish them (first), (next) refuse to share their beds, (and last) beat them (lightly, if it is useful); but if they obey you, seek not against them means (of annoyance). Surely, Allah is Ever Most High, Most Great."

So stay away from this woman in bed until she becomes righteous and undertakes her obligations which Allah has made incumbent upon her. But do not refrain from speaking to her , because it is not permissible for anyone among the believers to be estranged from his brother for more than three days, as was confirmed from the Prophet. In short, you may avoid speaking to her for only three days. As for the bed, you may stay away from her as long as you wish until she fulfills her obligations towards you.

Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 5 Pages 361-362