You don't need a developer. You need a "technical project manager". While there is some overlap the skillset is not the same. They need to be able to tell you that your project is undeliverable "out of spec" and you can either change price or method to get what you want cheaper. (E.g. Moving from native to web app in this use case can reduce costs by a third) a developer isn't likely to tell you that unless they want to lose money And can see it themselves. A cofounder will. They talk to you in terms of vison and what you imagine your users doing. Then they talk to the developers in terms of APIs/functions/subroutines for/while loops, new objects,etc. (the developers here will know what those mean) :-)
This question is so relevant in space I now occupy. By profession I am a Realestate developer who created with the assistance of an oversees programmer, who took forever to complete task.. Now that the project is complete I feel lost. The site functions and does everything I designed the site to do but now I need to find a tech co-founder who I can trust and depend on to continue the journey; any suggestion of where to start?