Eolian, do you also notice that DH gets to do the tasks he enjoys, rather than just what need doing? And we, as the women, are expected to be grateful for the contribution... it only works if the tasks he enjoys and does are the ones you don't and vice versa.
I remember when DS was five weeks old, and DH was about to go back to work so we had a practice day where I wanted to try and cope without him (expressing milk, really struggling with BF, post-EMCS). I lasted until about 10:30am, but I had a horrible realisation/feeling that DH could choose to be involved in DS's care - I didn't feel like I had that choice. We couldn't both walk away (not that it ever came to that). And it's always felt like that a bit. If DH isn't coping with 2yo's bedtime, he can check out because I'm there to take over. Never mind if I've also had a really crappy day and don't want to do it either.
It does work in reverse, but the knowledge that at the end of the day it could all fall to me as default is always there.