Hmmm, you made a mistake in not having your agreement in writing when you two agreed to work together. Having said that you must now move on. You have the code

Hmmm, you made a mistake in not having your agreement in writing when you two agreed to work together. Having said that you must now move on. You have the code, he doesn't have any rights for it. If you stay, this will backfire big time down the road. The partnership must rely on trust and respect, clearly not what's happening here. Move on.