It depends a lot on how you got together in the first place. Why did your startup need three co-founders? What was the expectation when you got together? Why do

It depends a lot on how you got together in the first place. Why did your startup need three co-founders? What was the expectation when you got together? Why do "you" need to define cofounder responsibilities equally? Usually the structure should be set up in the way the person who contributes the most ends up with more equity.