Actually, if you are enrolled on his insurance currently, most insurance companies require a death or divorce certificate before removing any dependents (in this case spouse) from the insurance plan. They have a legal responsibility to continue coverage once it is given (signed up) and cannot just drop you due to the participant 'requesting' it if you are currently enrolled and eligible. In the case of my husband, he could not remove his Ex from insurance without a valid divorce decree certificate. It is not as easy as one thinks, and in many cases it is impossible to take a spouse off insurance if you are still married.
