Is it permissible for a woman who fears divorce to buy a house through a usurious bank due to the absence of Islamic banks in her country, in order to secure housing for herself and her children should divorce occur?

What you mentioned about the possibility of divorce does not make usury permissible for you; it is one of the greatest prohibitions and major sins, and it is only permissible out of necessity. The limit of necessity is when a person is exposed to a state of extreme danger or hardship, such that he fears harm or injury to the self, or a limb, or honor, or the mind, or property, and in such a case, committing the forbidden act becomes necessary to avert the harm. So, fear Allah and mend what is between you and your husband and his family.