under the agency principle, unless he knows clearly that your hu*****and has no right to act on your behalf, you are estopped from claiming that your hu*****and's action does not bind you.
under the agency principle, if you hu*****and really do not have the authority to agree to the deal, you may file suit against your hu*****and to recover the damage, because he is not acting within his power.
and that's not all. even though the title of the car is in your name, depending on your state law, you hu*****and might have interest in that car as well. so the assumption we mentioned earlier might not stand be begin with.