It’s a tough one, i lucked out on my first co founder, we went 50:50 and it went really well, but we were both contributing heavily and both have very easy goin

It’s a tough one, i lucked out on my first co founder, we went 50:50 and it went really well, but we were both contributing heavily and both have very easy going personalities. On another one it was a complete disaster with a personality split not unlike what you describe, and the work load very unevenly split with me doing most of the work. I think I unfortunately went into that one a bit naively based on how well my first startup cofounder relationship had worked out. Following that I decided moving forward that unless dealing with someone I had already worked with, that it was best delaying the founder splits until I have a better understanding of how the other person performs. In my experience people do not really change, so yes your guts are probably a good early warning system you should listen to. Since you already did a 50:50 split, I think if I were in your situation, before doing anything else, especially any fundraising, I would lay out the issue with your cofounder and see if things can be worked out. You could for example both agree that additional contributions from you moving forward should be compensated with additional shares.