1. No one wants to partners with a guy that can't code and hope he can learn to become a technical cofounder from scratch. Typically speaking, you find someone with coding chops. The same is true of business cofounders BUT unfortunately most idiots don't realize they don't have the business knowledge needed to be a good business cofounder.
2. Your cofounder should NOT be waiting around for the product to finish to do his part. There is a SHIT TON of stuff a business cofounder can do while waiting for the prototype to finish. In my honest opinion, if he doesn't know what to do, he should be hauling ass to figure this out or he's not pulling his weight. I'd argue that in the long haul, while the technical guy mostly codes and do some of the other stuff, the business guy got a lot on his plate. If he sucks now, he'll do even worse as time progresses.
3. I hope to god you guys formed a business, have vesting in place, and so that if things don't work out, you're not going to run into more issues than necessary to make this separate clean. And no, just because you guys agree to separate on good terms does not make it clean. There is a process for this.