In short - earlier post is wrong - it depends, if you were the only signaturee there is a legal debate which suggests the one who didn't sign can hardly be bound the terms and conditions therein!
Presumably the divorce did not sort out the tenancy?
However your new husband has a right to occupy what used to be called the 'matrimonial home' as he is your husband. Therefore no real advantage in him becoming a joint tenant with you
Go to local CAB and get their advice.