Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
We (Iftaa` Department) have already given the ruling of Sharia on working for non-Islamic banks in Fatwa No. (
467). In this Fatwa, we have made clear that if the employee`s duties involve facilitating usurious transactions or extending assistance to that end, then his/her work is unlawful. If it isn`t as such, then it is lawful.
If your husband`s work involves that which is unlawful then try to remind him, with kindness, of Allah`s limits and that one who does such work is cursed by Allah. The evidence on this is that the Messenger of Allah said: "Jabir said that Allah's Messenger (PBUH) cursed the accepter of interest and its payer, and one who records it, and the two witnesses, and he said: "They are all equal." {Related by Muslim}.
In any case, you (Questioner) are cleared from liability before Allah as regards what he spends on you from his salary. This is because part of this salary is received against facilitating usurious transactions while the other is for performing lawful tasks at that bank. Jurists (May Allah have mercy on their souls) stated that it is permissible to accept maintenance and gift from one whose money is a mixture of that which is lawful and that which is unlawful as indicated in Fatwa No. (
486). And Allah the Almighty Knows Best.