My dh is a mechanical engineer who co-owns an oil and gas engineering company with a fellow college alum. They design, manufacture, sell and support downhole drilling tools for oil and gas wells. I can, in general, explain what the tools do and why they're important and necessary but if he tried to explain them to me in further depth, my eyes would glaze over. I am also able to convincingly ooh and aah over his tools and act impressed when they remodel their building or add onto it. I also act supportive when he comes home stressed or has to travel or work late. I figure that's all I need to do.
I'm a SAHM. He thinks he knows what I do all day, including spending too much time on the Dis (according to him), but he really has no clue. I think he thinks there's a magical toilet paper and dry cleaning fairy who make these things magically appear in our home.