What is the ruling of the Sharia regarding a wife staying with a husband who loves her despite his family inciting him against her and their ill-treatment of her, given her fear of her home being ruined?

It is your right to have independent housing. If your husband's mother orders him to divorce you without a valid reason, she is not to be obeyed. It is not permissible for him to honor his mother by wronging you and depriving you of your rights. Rather, he should combine honoring her with treating you well.