My situation is a bit like yours as in my DH works very similar hours and is physically and mentally exhausted (office job, but multiple locations, lots of travelling, and high pressure). In the week, the DC don't see him at all as he leaves before they're up and gets home after they've gone to bed.
I can only tell you what works for us. Firstly, it felt a lot better once I was back at work so I wasn't with the DC all day every day. Secondly, we share the chores at the weekends and both get a break too. For example, DH has a lie-in on Saturdays and I have a lie-in on Sundays. We might all go and have breakfast together but then the other one gets to go back to bed for a bit whilst the other one clears up and gets the DC dressed. Just being able to go back to bed with a cup of tea, a bit of time online or reading, then showering and getting dressed in peace can really set me up for the day.
He will do the meal plan for the week, then he will take the children out to park or somewhere for some quality time while I go to the supermarket and buy all the food. I get time to myself, but he's actually done the hard work planning it all out.
He cleans the kitchen and I'll do the washing, etc, etc. You get the picture.
Oh, and we'll both start bedtime together but then one will do the stories and the other goes downstairs to crack open the wine and watch a bit of TV. So we've both shared the shitty bit of bedtime (negotiating with DC about going upstairs, getting changed and washed) but one person does the stories which is still a lovely time and the other has a quiet drink.
Hope some of this will help, and I hope it will all feel a bit better when you go back to work. 