I don't think that it is against the law but you will DEFINATLY have a problem when the secondary insurance finds out they have been paying as the primary. Also when your husband completes his application to have your daughter covered he will have to list any other insurance and if he doesn't list it then if they find out they can deny all of your claims and completely invalidate their coverage possibly leaving you with lots of money to pay them back. Insurance companies are not in the business to pay out money and if they can find a way out of it they will.