Housing one's wives and children

Q: I am an eighty-year-old man and I have two wives, but I have no fixed source of income. One of my wives lives in Tabuk while the other lives in Al-`Ula, in Madinah. Thanks to Allah, I was able to buy with my own money a piece of residential land for my wife who lives in Tabuk. I applied for a loan from the Land Bank in the name of my son from this wife living in Tabuk. The house I built is composed of two floors; the first floor for my wife and her children and the second floor is divided into two apartments. My son lives in one apartment with his wife and children and the other is rented out and the rental money is used to support my wife and children who live in the same building in Tabuk. Later, I bought another piece of residential land in Al-`Ula with my own money without anyone's help. I applied for a loan from the Land Bank. I built a house of two floors, each having one apartment. My wife and children live on the second floor while the first floor is rented out and the rental money is used to support my wife and children. Each of my wives has her own apartment and receives her sustenance from the rented apartment in the same building. The problem is that my wife who lives in Tabuk wants me to empty the first floor in Al-`Ula building to stay there when she comes during (Part No. 21; Page No. 164) the summer vacations. This will leave the apartment empty the rest of the year; and she already has her own apartment in Tabuk, an apartment for her son, and a rented apartment to support her. I fear Allah (Exalted be He) and I am Multazim (a practicing Muslim). I want to free myself of any sin that I may incur because of my wife's request for something she does not own. I hope you can guide me in this regard. Does she have any right to one of the apartments in the building located in Al-`Ula where my other wife is living? I do not have a fixed source of income and each of my wives lives in her own building and her sustenance comes from a rented apartment in the same building. Please guide me in order not to commit a sin. May Allah safeguard you!