You're still very early in the project. You have paying customers, but it sounds like that's more-or-less just covering hosting costs, etc. You have a long way

You're still very early in the project. You have paying customers, but it sounds like that's more-or-less just covering hosting costs, etc. You have a long way to go if you're going to turn this into a real business that makes you rich. A long way to go where you'll be working with this guy and splitting your profits with this guy. Talk to him about your concerns and see if you can work something out. But if you have any doubt that he's the right cofounder for you (which it sounds like you still will after talking to him), get out now. The longer you wait, the more it'll feel like you should just stick it out because of how much work you've already done and how well it's going. But though it may feel like things are going great right now, you really haven't invested that much time in this, and you don't want to spend 5 years with a cofounder that you don't feel is pulling his weight. If you don't think you can spend 5 years working with this guy, get out now.