If your DH has a (jointly agreed) parenting responsibility like bathtime, making packed lunches, last feed, taking to ballet, whatever, how often does something 'more vital' crop up meaning you do it instead?
How often is it really more vital?
If he shows signs of 'being busy' do you
a) march in on the dot of seven and hand him the baby
b) wait 20min then ostentatiously but passive-aggressively stomp around doing said task
c) just do it yourself without fuss
d) other?