In today's modern world, we are intentionally ignoring the rights that were given to us.
8 hours a day was fought for. 40 hours a week was fought for. If you are expected to exceed these limits without compensation, you are being ripped off. You have limited time in this life.
As a developer, you create tremendous value in this world. If you didn't you couldn't demand the salaries that you demand. If it was easy, then the business guys would be learning it and doing it for themselves.
It's a modern skill required by modern business. You should not feel like you are forced to spend every waking moment eating, drinking and sleeping code.
In my personal experiences I have found that I have to force myself to step away. After a few hours the wheels stop spinning, but when I come back I am always excited to work on something. This is far more desirable than feeling the dread that comes from doing something non stop.
Balance is extremely important, I do not understand the opposing viewpoint that we should all be code robots.