I don’t get it either but it’s so ingrained culturally that it seems that even the most intelligent and independent women get caught in the trap post kids. My DH is excellent, he carries mental load and shares all the chores and probably does marginally more childcare. He sees what needs to be done and gets on with it, you can find him vacuuming in his lunch hour when WFH and he bakes a loaf of bread every other day, he will pack the kids bags and know what clubs they are doing that day etc.
But there’s still something about the thinking, planning and anticipating that I do that he just doesn't. He lives in the moment. He gets what’s on the list from the shops, he doesn’t hold a meal plan in his head, he gets an outfit out for the kids, he doesn’t think about whether or not to avoid putting DS in his favourite t-shirt for a messy activity. That kind of thing - sounds small but it adds up. It was fine before kids - but kids are so much about the thinking, planning and anticipating. Even with a committed, equal DH, it took us a good while to find an equilibrium and I felt mentally overloaded for a long time.
When I was on mat leave, I’d saved to continue to contribute to the household financially. I also made it very clear I was at home to look after the child and build my new life as a mum. Not to take on a housewife role.