If you are working for nothing, all the work product (code) is yours. (There is no transfer of copyright document, right?) Quit, and bring your code and the one other guy and start your own company. Probably need to sue the leech for breach of contract, too, to dissolve the old thing cleanly.

An idea and $5 will get you a Starbucks.

(This is not legal advice. Do get a lawyer. They might have smarter ideas.)