I know what you mean. Three months back I was in exactly the same situation. CEO and founder, ran two businesses, and never was truly an employee.
I tried contracting, but unless you are technical or a designer, you'll end up being a c-suite consultant for startups. And at least where I am from, most startups don't pay for this sort of advice or involvement.
So I ended up taking a c-suite job in a small but relaxed startup. Not very fond of their relaxed attitude, it almost irks me. But at the same time I was also burnt out like you and still am to some extend. I guess I'll need to do this for another few months. But then it's back to founder's land to me I'm afraid. Being an employee has its perks but also its irks of not being the main driver of everything. So you'll have to settle for having it "their" way. It's also going to be unsettling for you to have idle time. I never had idle time before, and the first few weeks I got really paranoid about being laid off soon because I'm not doing 120%. Luckily, this is just the norm... a norm I wasn't used to.