Really? That is certainly unusual. Please detail your schedule, since you made your claim.
It’s not all that unusual. Any good teacher, and I know there are plenty of bad ones out there, but any good teacher surely logs that many hours, if not more. My mother is a kindergarten teacher. Whenever I feel tired or overwhelmed, I just look at her. She rarely comes home before 6:00, and spends, on average, at least 12 hours in her classroom every weekend.
The sheer volume of work can be staggering. I try to have two graded assignments for each class every week. I have 150 students. Therefore, I grade at least 300 papers every single week (and good teachers grade for effort and accuracy, not simply completion). I’m also in the process of grading 70 literary analysis research papers. A good one takes about 20 minutes to grade. The ones that are, let’s say, problematic can take much longer. I teach three levels of English (freshman, sophomores, and juniors), and that means preparing three different sets of lessons and materials every week. I usually have to devote at least an entire Saturday or an entire Sunday every weekend to preparing for the coming week and grading any leftover assignments from the week before. I’m starting to put a few restrictions on myself. My latest rule is that 8:00 PM is the official cutoff for the work day.
I love my job, and I’m good at it, and I feel very accomplished to see the progress my students have made this school year. I don’t have complaints—I work hard because it’s my responsibility to educate my students to the best of my ability. And that takes time and dedication. So I don’t mean to whine. But when people act as though teaching is some cushy job, I’m irked.