> I hate meetings and trying to seel our product so I am glad someone is doing that.
This is your answer. They're doing things you don't want to do. Now, they don't have to have equal ownership per se. But you need to decide how important they are to you, and they'll respond by letting you know what they want to do the job. And that very well might be a 1/3 split.
Also, keep in mind that the hours put in by each 'department' does depend on the state of the product. In the early stages, product development takes up nearly all of your time. Once you get a product that can be sold, marketing will consume a lot of time. And once you have customers and more employees, the business crap will take up a lot of time. Also, don't discount those two factors. Think of all the shitty products that have and still continue to be sold thanks to good marketing and connections.
