He does sound selfish/thoughtless.
I did initially think, why don't you just text him, but I've since read your replies that if you do that and he's not going, he won't alter his plans. Is he stubborn? Or just a bit dopey?
Time to get some answers ready:
"I'll be out of nappies by then, would you like me to wrap little Freddy's arse in a towel til then?"
"It can't wait. I need X today, if I wanted it tomorrow I'd have said so."
"You're not going? Great. I could do with a break. You don't mind finishing the cooking and feeding the kids while I go then?" (Then drag out that shopping trip so he wonders where on earth you've got to!)
"You need a shirt for work? I'm not doing ironing today/tomorrow/this week."
Or, the night before..."When you're next going to Tesco, here's my list. I'll need it by X day though at the latest." (That'll take a bit of forward planning, so you've got enough to last).
Do you ever get cross with him? Like really cross and put your foot down?