What would happen if you just *stopped* at 40 hours? Miss some deadlines? Let your lazy coworker earn her keep.

Three weeks ago I stopped going above and beyond, stopped working all the extra hours (for the most part). I feel sooooo much better. I actually have some time and mental capacity to start planning my escape.

I hope you find something better soon. I saw your other post - that place sounds awful and your boss sounds like a jerk who wants to cover his butt.