[mindhash]

A thing about long lasting relations is, both parties are comfortable discussing anything under the sun. So you must open up a channel around this and express your concerns.

In my first startup , my cofounder was interested in design and would spend needless amount of time on it while his core job was to go out and sell. Honestly I couldn't get my thoughts across to him and left the startup. Probably a noob move now I think about it.

Have a discussion about mutual exclusivity to get most done as a team. Tell him you believe in MECE and what his thoughts are about it.

Also sometimes you can be more accepting to his coding interest and let him do a few stuff. But you must remain gate keeper for the final version of product. Have processes setup for this. You could mention that you are not comfortable having more than one person handling releases.

I have learned from my experience that it's important to have most difficult discussion early on with your cofounder.