I agree he needs to support you more, either physically at weekends or by providing outside support (or both) but I would also say, this time will pass.
It sounds like he has a good job and an opportunity to progress and is a trusted employee.
When my dcs were tiny, dh was working abroad most weeks. I was you at home alone, which at times was exhausting and dull, and as you say you never get a day off, or a lunchbreak even! But now my dcs are a bit older, I am the one travelling abroad for work trips whilst he is mostly UK based.
Looking back I took the back seat to allow him to provide for us and progress his career, we could do that as I was home full time. Now he is UK-based and I am taking the trips and he is the one getting them out the door with homework/kit/instruments etc and checking the evening homework whilst I skype from a foreign land. We are a bit like weather vanes when it comes to our jobs, we can't both be out front at once, one has to stay back. Now it's my turn to catch up. He will be looking to change his job in 2016, so at that point if he needs to put the hours in as the new boy, I have enough good will in my company to delegate my travel to others and take a step back, or at least stop pushing forward.
Whilst your dcs are tiny, this is his time and you need to agree with him that your time will also come, to keep the balance in your relationship. It's a team effort and only one person can be scoring goals at any given time, someone else needs to line up the balls until it's their turn to get a kick at goal. Play the long game.. Sorry for rubbish football analogy!