It's possible if you unplug from work and don't sit in front of a screen in the evening.

I can't be the only software engineer whose brain is constantly trying to solve problems, regardless of where I'm sitting...

Yes, but that is something you can change with practice. It's going to be hard at first though.

I've been trying for the last 30 years or so (don't really remember it being an issue until after early teenagerdom). When does it get easier?