Is it considered an act of disobedience towards his mother if a husband takes a separate apartment for his wife, knowing that the condition of sharing accommodation with the mother was made by the wife before marriage and the hoped-for harmony has not been achieved?

The wife must fulfill the condition she agreed to at the time of the contract, which is to waive her right to a separate dwelling, based on the words of Allah Almighty: "O you who have believed, fulfill [your] contracts," and the words of the Prophet, peace and blessings be upon him: "The conditions most worthy of fulfillment are those by which you make intimate relations lawful." However, if living with the mother results in demonstrable harm, she may demand a separate dwelling to preserve her privacy and circumstances, prevent disputes, and act upon the fundamental right of a woman to have her own private residence. Therefore, there is no harm for the husband in taking a separate apartment for his wife, and this is not considered disobedience to his mother.