My dh is currently working away on a project - flies out early evening Sunday, back late Thursday night, works from home on Friday. Been like this for 5 months now. We have 3 school age DC and I work FT.
He has worked off and on on projects since we met so in theory this is nothing new. We have no family help but I have used a variety of au pairs and nannies to help before.
This time round has been so so awful, and I think it is because the children are that much older now (a year or so younger than the OP's dc) and they have more activities to support. All I do is rush to get them to school (breakfast club) in the morning, rush to work, some nights rush back because I need to take someone to an activity while the nanny goes in another direction, some nights I can work late. Weekends are more taxi driving, laundry and batch cooking.
My dh is v supportive while he's at home, but he is increasingly distant from the 'rhythm' of the family, so he's operating at a 'task' level, rather than really taking ownership.
It is only an existence (and I don't mean to sound melodramatic). All the burden is on me, and I have been expected to cope. Which I am. But it is miserable.
It's a hell of an ask on your dp that they pick everything up while you are away. And then your weekends will be sheer drudgery trying to get set up for the next week away. At least my situation is due to end soon, but you are contemplating a permanent arrangement.
The only way I could realistically see this work on a longer term basis for our family is if I worked shorter hours - but we can't afford that.