I had this problem.<p>I told him it wasn't working out and found another co-founder. I was lucky because the entire ideas was mine and I was a developer. I brought him on board because I thought he could offer some expertise and help getting the company off the ground. I was wrong.<p>I also never partner with "idea" guys. Why? They have no idea how long something will take and in my experience, can easily just leave you when they get bored with the project. I had 2 ex-co-founders do this.<p>After a few months in, they decided that the project wasn't happening fast enough and move onto something else. The issue is that if you do become successful, they will most likely lay claim to your work. Even if it doesn't hold up in court, it's time taken out of your life.