Yeah, it sounds to me like this person isn't the right fit for you. My initial reaction to the fact that you've already gotten the project rolling is that you'

Yeah, it sounds to me like this person isn't the right fit for you. My initial reaction to the fact that you've already gotten the project rolling is that you'll want more than a 50% share in the resulting company, but you should find someone who you want to share the other 30-40% with who will actually help bring the product to market. If you create something people love it won't be difficult to market when the time comes.