Maybe I just need to stop doing stuff. But then it just won't get done. He's like "I'll do it in my own time" but then weeks pass.
And if you ask, you're "nagging"?
Very easy answer: "would you take this approach to work tasks?"
It's a complete cop out that men use. I mean sure, of course he can do things in his own time, but there's still always a deadline - the point at which the kids' clothes are unwearable or inappropriate, dinner being so late that everyone has eaten 3 sandwiches, teeth falling out because you haven't seen a dentist in 2 years, increased cost of your insurance because no one is shopping around.
Perhaps a good one to hand over is things that have specific deadlines and are kids related - so, for example, we have various things that have to be paid at various times on deadlines that are external (ie no whining that YOU are setting unreasonable/unfair deadlines and you're "not my boss") - clubs, school dinners, dance classes, football subs etc etc. He's welcome to do those in his own time, but if he misses the deadline, he must understand the DC will be the ones missing out.
To be honest, food shop, cooking and clean up is actually quite a big task. I don't particularl ymind doing it, but it's the one area where I think even though DH takes quite a lot on, that one is such a BIG one and it's so bloody relentless that sometimes I feel I shouldn't actually have to do anything else! 
[Note, I'm about to go and top up DS' school canteen account and order DD a new t-shirt for her dance class. Because it's never bloody ending so I get it]