D.B.
I put it in my calendar. Can you do a family cook day on Sunday and make a week's worth of meals? There are lots of great recipes out there of how to combine different things into meals that don't look the same! You and your husband can/should switch off nights. Consider whether the kids need baths every single night. After summer days in the sand and mud, yes - but maybe not all year round. Maybe just a damp rag??!! Really!
Can you squeeze in some exercise each morning when it's quiet? What time do the kids get up? I used to work out and my husband dealt with our son from whenever he work up. It was great time for them, and they didn't come into my area unless someone was on fire or bleeding! My son learned that exercise was important, and that Mommy deserved her own time.
Can you combine any activities? Run while walking the dog, read the paper while on a treadmill, listen to recorded meetings while working on a balance ball or doing bicep curls? You can do slow weights while watching TV, and do cardio maybe 3-4 days a week under other circumstances.
And, what can you cut out? What are you doing from 5:30 to 8:30 that doesn't have to be done? If someone's relaxing and watching TV, that's a good time to fold laundry, obviously. I do grocery lists and cut coupons during commercials, and I have my laptop there and answer emails.
My husband and I unload the dishwasher together - we each stand on one side and unload whatever goes in the cabinets closest to us. We also tag team on the groceries - I do the big shopping and call him when I'm 5 minutes away so he's ready to unload & put away. He does the "fill in" grocery trips for milk or fruit, and puts everything away. He does more of the laundry since he's a runner and needs to get that stinky stuff done more frequently.
I think it's fine if the kids know that tonight is Dad's night and tomorrow is Mom's night, or tonight is sandwiches.
Speaking of which, do you make a week's worth of lunches and then freeze the sandwiches? My mom did that 1000 years ago, and I did it too. Lay out 20 slices of bread for 2 kids x 5 sandwiches, layer on the turkey and cheese or the PB and J, put the "lids" on, and wrap & freeze. Each morning, pop out 2 sandwiches for 2 kids. I pre-packed snack sized containers of fruit, carrots, granola, whatever - Ziploc makes some little containers about 1/2 cup in size. I lined those up, put cheese cubes or mini carrots or raisins or berries or whatever in them, and stacked them in the fridge. Easy to grab & go in the morning. I also pre-mixed drink bottles so as to save on the junk sugar drinks - using reusable metal bottles or BPA-free plastic was great.
Good luck! Take care of yourself and everyone will be better off!