Does your spouse have homework?
My mother was a teacher. Her time in the classroom was nominally from about 8:00 - 2:30. Her time actually at work was from about 8:00 - 4:30, because there would be students with after-school activities that needed supervision, or staff meetings, or parent/teacher conferences, or putting away classroom activites, etc. Her time away from home, including commuting, would be about 7:30 - 5:30. Her time actually working or commuting to work would be 7:30 - 5:30 + 8:00 - 10:00, because she'd frequently have to spend another couple hours grading papers, or writing up feedback, or planning the next lesson. She would often end up going back to school up to a month before the kids came back, too, to research and plan lessons.
I think the "teachers don't work all that much" meme gets confused by equating time in classroom with work. If you're doing it right, teaching involves a lot more than just delivering instruction to kids. It requires that you really understand each of your students (which could be 20 in elementary schools, but up to 100 in high schools), and where they're at, and that you understand your subject enough to bridge the gap between student and subject. That takes a lot of time, probably more than most industries.
Of course, this all gets confused because there are many, many teachers who don't put in that effort and just deliver a pre-canned lesson plan to 20 bored minds every day. They get up, talk, and go home. Those are the teachers that made my childhood hell.
The unfortunate part is that the way economic incentives are set up, there is no reason for a teacher to act like the first description, and every reason for them to act like the second. Anyone who's willing to actually understand the job they're tasked with doing will put that effort into a more lucrative job (well, except for a few poor schmucks for whom teaching is a calling). So you do, in a sense, get what you pay for.