Coming from a similar background. I
am that guy who thinks about my start-up 24x7, more than my other 2 founders. I've also worked along my cofounder at my last company where not all went well so some of those feelings carry over(and I have to be mindful of it!). Also, I've realized that I also have crazy downtimes or crashes that are bigger than them. In those times, I appreciate the stability and the calm in the other founders. So I'd challenge you to make a list of
positive characteristics in your partner that aren't necessarily in you.
Honestly I think a lot of your issues might be with not being in the same room. I know one of our founders' recently spent a week away and it was pretty evident that things were getting uncomfortable.
We didn't have much resistance. If anything, this is good because doing a start-up is scary enough and doing these calls helps build confidence and reduce self-doubt. And you are not constantly second guessing about what other partners' feel about the other because those feelings are expected to be shared on a regular basis in a constructive manner.
On one of our very first calls, I was called out for being overtly negative. Of course that made me even more defensive in the moment. But that evening I took a step back, realized I was kind of at fault(even if my concerns were genuine) and wrote a plan and shared with the team to get me to a point where my attitude doesn't come in the way of airing genuine concerns.