i'm leaning towards leaving, as you didn't once mention the passion for your company. Do you still enjoy the "work" aspect of things, working on the product or service and figuring out ways to get it to the masses? Or does it seem more like a grind to you? If it's not 100% yes on the first question, maybe it is time to leave....
if the answer IS yes, then maybe, aside from the other great suggestions, is look for a "co-founder" therapist. These people can come in and help mediate communication between you and your co-founders, and hopefully help root out the problem.