I've been married to a workaholic for over 20 years, and many of the posts on this thread resonate with me.
We started off in the same job along the same career path, and were both quite ambitious. When we had DC (planned), something had to give and that something was my career. H is now a high-flyer, and I've taken a sideways move onto a pathway that is not as well-paid and is harder to progress in without large investments of time, which I don't have.
He works all the time, by which I mean all day and into the night until 3-4am, 7 days a week. The first thing he does every morning is turn on his computer. He insists on working in the middle of the main living area, which means that the DC see him perpetually working. He has no hobbies or friends. I do 99% of domestic and child-related tasks, including the ones which are traditionally masculine like DIY and car maintenance. I work full-time but can't really put in the extra hours needed to progress, so there is now a very large discerpancy in our respective salaries even though we started off at exactly the same point.
Over the years he has refused to go on holiday, refused to do more around the house, refused to share out school runs and refused to take time off when the DC were ill or when I needed to be at work during school holidays. Everything he did around the house was optional and done on his own terms - I was the default, and he only chipped in if and when it suited him. At one point he told me that he was perfectly happy with the way things were, so my dissatisfaction with the imbalance in our roles was not his problem.
About 10 years ago he had an inappropriate relationship/emotional affair at work. That was my wake-up call. We didn't split up, for complicated reasons which meant I genuinely believed the DC would be worse off if we had divorced. But I stopped thinking of us as a partnership - because with hindsight, we never really had been one, I'd just been his support system. I arranged my life so that I didn't need his input. If he refused to go on holiday, the DC and I went without him. I cooked one meal and ate with the DCs rather than hanging around wondering when he'd be home so that I could eat with him. I planned holiday childcare so that his help wasn't needed. I stopped asking for his input about decisions relating to our domestic life and arranged things in a way that worked best for me.
It saved my sanity, and I think (I hope) also taught the DCs that you don't need to pander to a workaholic to your own detriment. The sad thing is that now that the DC are teens, he does try to become more involved in their lives and offers to do more with them, but they aren't that interested because he just hasn't been present in their lives. It's his loss - they're great kids.