This might have been assumed, but it's worth reiterating that this could get really stressful and distracting for your business. To avoid that, you should do ev

This might have been assumed, but it's worth reiterating that this could get really stressful and distracting for your business. To avoid that, you should do everything in your power to leave on good terms with him. First, talk to him in a non-confrontational way: ask him if there's anything that's getting in the way of his giving the project more attention. Politely let him know that you expect more of him, as a business partner, and see if he steps up. Set a concrete but reasonable goal date (I'd do about a month from now), and on that day, decide if you want to keep working with him for the next year or not. If you leave, suggest getting back together after he has a chance be more focused/organized/whatever. I wouldn't bring lawyers into something like this until the very end, as they can put a very grim aura on the conversation. Have a heart-to-heart, figure out what you want, what he wants, and how both of you can be satisfied. Once you're sure of that, see a lawyer about making a legally binding agreement.