Spikes - you have my sympathy. I'm married to one the same.
Our middle kid is chronically and seriously unwell. He never visited him on the ward until the child was 8 and asked "why do the other daddies come to hospital, but, not you?". He has never come to a parents night at school. Every evening, weekend and holiday is hijacked by work. I was once ill in hospital and could have come home but he was working late in the office and persuaded me to lie to the staff so I could stay on until he could come for me - at 10pm, it was my birthday to boot.
I have made my peace with it - and sorted out my own emergency cover. But, I no longer pretend that he is helpful or make excuses for him to anyone. Including to his mother and our GP.
The thing that I get angry about, proper angry, is that we are, after all, married. He promised "in sickness and in health", he is not keeping that vow - and, he never will. I may, sometimes, loudly point out that the marriage vows are not weighted, that just because he's not shagging around he's still damaging his marriage by neglecting us when we need him. His answer "there are people at work who depend on me too"...
I've suggested him leaving his job, we can sell up and live mortgage free in a smaller house, somewhere closer to our families. Nope. I've suggested reducing his work hours so he can do some school runs and I'll work part time. Nope. He wants me to work, do everything at home, cover all the holidays, hospital appointments and school appointments whilst he brings in the cash. It's almost as if I am a member of staff he's outsourced the jobs he doesn't want to do. His entire identity is wrapped up with his job.
I love him, but, my resentment is slowly growing. We've been to marriage counselling, which helped, but, in reality, there is no actual change. This is why couples divorce in thier 60s or 70s. If that turns out to be us he'll be surprised and think it's unjust, "I worked so hard for you all". He can't see that all we want is HIM!
He's not a bad man. He's just unable to see my point of view, I expect because our marriage is modelling his parent's marriage - he hardly saw his dad, but, he had a responsible, high profile role.
I feel for you. But, it's not going to change and it is wise to work out a series of Plan B's. Have a pot of money to cover emergency care/taxis/short term cleaner. Have non-negotiable nights out/weekend with friends. Have a hobby/exercise that you do regularly, just for you. When you're running low on oomph then lower standards are acceptable - my kids have had days on end of screen babysitters, breaded chicken product, free access to the treat cupboard and pj days/weeks. Does them no harm, cut me some slack.
The good things? My husband is a great role model for work ethic - and I am a great role model for nurturing, so the kids get a good balance. They'll never know what it is to be hungry or in uncertain accommodation, and that is not something I take for granted. He loves us, this is his demonstration of love - it's not what we WANT him to do, but, that shouldn't negate that it is done as a gift for us. And, he's actually happy, he's thriving on the stress and drama and being in a responsible role.
Look after yourself. Work out your boundaries. Stick to them. It's possible to make it work, but, it's a huge and exhausting effort.
Hope you feel better soon.