Before your hubby goes to work, get him sexually aroused. Offer him a list of guidelines he must carry out the moment he gets house. Not allowing him to orgasm is the easiest way for a new Mistress to get easy control of her brand-new servant.
Continue in these "games" until you feel the time is best to talk with him in a major manner about your relationship. He will have shown to himself and you that he is submissive; also, you will have shown that you are dominant. He will also know that he takes pleasure in the brand-new plan because he will be having fun.
You want him to become your slave. At this point he will almost definitely state yes, however you have actually done it in such a way as to give him a choice in the matter. He can then decide if he wishes to become your slave.