First, it sounds as though you have applied for Supplement Security Income as opposed Social Security Disability. SSI is need based and is available to people who are disabled who have not worked enough to qualify for SSD where as SSD is not need based and is instead based on your history of earnings. For whatever reason, it sounds as though the administrators who processed your application have determined that you and your Husband live together. You might have appeal options, but you will probably need to act quickly to exercise those appellate options. My specialty is not Social Security, but I have changed the practice area so that hopefully some attorneys that practice social security law will be able to assist you.
I will also suggest that what has happened to you is a good example of why it is important for people who are no longer living together and have no intention of getting back together with their spouse should obtain a divorce. Another example of the type of complication that can arise from not getting a divorce include being held responsible for certain debts incurred by your estranged spouse (including debts for medical bills) under the doctrine of necessaries. It might cost a little money to hire an attorney now to assist you with obtaining a divorce, but it will be worth it in the long run.