Is a husband considered to be harming his wife if he refuses to divorce her, while she insists on wearing the hijab and refraining from dealing with usury, knowing that the husband is aware of her psychological distress and feelings of instability due to this commitment?

Your decision not to resort to forbidden transactions is correct, and your wife should support you in it. For whoever abandons something for the sake of Allah, Allah will compensate him with something better. And whoever fears Allah, He will make his matter easy and provide for him from where he does not expect. It is not permissible for your wife to seek divorce for such a reason, for the Prophet, peace and blessings be upon him, said: "Any woman who asks her husband for divorce without a sound reason, the scent of Paradise will be forbidden to her." Your refusal to concede to her desire for separation is more appropriate, and there is no sin upon you in it as long as you have not withheld any of her rights. We advise both of you to be patient and overcome your disagreements. You should provide for her from what is permissible, without extravagance or stinginess, and without earning from the unlawful. Allah Almighty says: "Lodge them where you dwell, according to your means, and do not harm them so as to make their lives difficult." Increase your supplications that Allah may grant you affection and mercy, and that Allah may set your wife's affairs right. And I advise both of you to be patient and to fear Allah, the Mighty and Majestic.