This. As a teacher, I could make about $45k a year, working through the summer. Work through the weekends on lesson plans, and through the evening grading. Easily 60 to 70 hours a week. Winter vacation and spring break might allow me to catch up on grading as there is always more to catch up on. As a software developer, I make over twice that. I typically work 40ish hours a week, and have vacation.
Why do you have to grade so often? Aren't you responsible for deciding how much work to grade? Are you certain assigning homework is the most effective way to gauge student understanding of concepts?
That's something I'll never buy about teachers. All of the ones I know complain about how much time they spend grading papers. I just want to scream "Stop assigning homework!"
Honestly, maybe what we need is new and creative teaching methods that happen in class rather than just piling on work to the students.
(Don't take this as a slam on you, I'm just curious why teachers always go the "Give them homework" route. Kids end up with hours of homework all the dang time.)