Personally, I'd talk openly with him about this and a real division of labor. If he is willing to put in equity and you're willing to put in sweat equity, for

Personally, I'd talk openly with him about this and a real division of labor. If he is willing to put in equity and you're willing to put in sweat equity, for instance, a 50% split can be reached. If he's not willing to put in either, drop him. If you can, offer to buy him out for whatever you think the idea is worth. If not, go your own way.