How can the questioner rectify her husband's mistake of buying a house with an interest-based loan, and is she considered sinful for residing in this house?

May Allah reward the questioner for advising her husband, for this is the characteristic of a righteous wife. If a wife advises her husband and he does not respond, then he bears the sin and nothing accrues to her, for Allah Almighty says: "And no bearer of burdens will bear the burden of another." Borrowing with interest is forbidden by Islamic law because it is usury, and it is one of the major sins that are not permissible except in cases of dire necessity. The husband must repent to Allah and resolve not to return to such a sin. As for the house he bought with the usurious loan, it is permissible to benefit from it.