I am wearing hijab but I want to take it off because of depression. Is my husband a sinner because of it or only me?

The hijab is a personal obligation upon every Muslim woman and it is impermissible for your husband to permit you to remove it. Therefore, you must observe wearing the hijab as much as you can to please Allah and not out of being forced by anyone. Hijab is a Divine obligation upon every adult sane Muslim woman. Therefore, if you are weak or fail to observe this obligation, only you are blameworthy and not your husband. Your husband must continue to offer you advice until you observe wearing the hijab. Be optimistic and know that Allah has legislated legal obligations for our benefit and to put us on the straight path.