I went down the wrong path for a long time, and like the frog I did not notice I got burned.

My advice is to be honest, with your self, your co founders, employees and customers. Tell them you cannot meet the deadlines and stop working so much.

No one is angry when you move the deadline up front, only when you do not tell anyone you cannot meet it.

And remember that if they matter they wont mind and if they mind they dont matter.