A little late to the discussion, but what I missed in the comments was to properly try to reestablish the relation with your co-founder at least once more. It

A little late to the discussion, but what I missed in the comments was to properly try to reestablish the relation with your co-founder at least once more. It sounds like it will take a lot more than a meeting. The two of you should go on a three day retreat to discuss the company situation and strategy deeply and to repair the connection between you two. If you have completely different views, in a way that is really interesting and you should both strive to fully understand and learn from each other. Who knows what lies underneath the difference in views? Once you know that you can make a much more informed decision and if you still leave it will likely be on much better terms.