I think the OP posted this in AIBU as she finds it odd that some MNers do seem to find her perfectly workable arrangement U. There will always be those who say YABU and those who say YANBU. It seems daft to question her choice to post though.
I did most of our family laundry from the age of about 12...it was a perfectly easy chore to cope with...and one which I have happily kept into adulthood. During big family get-togethers with sister, grandparents, nephews etc. I still do the lion's share of everyone's laundry. Can't bear it not being sorted properly (OCD?!). However, I rarely iron.
I think OP has come up with a genius plan which keeps her happy and her DP just gets on with his share. It doesn't sound like he is resentful (why would he be?), they are HIS clothes. It wouldn't be my system of choice but it works for the OP and her family. Good point about teaching their DS some independence too. Must remember to think of something like that in a couple of years when our DS begins the "training to be a bearable partner in later life". Oh please let me be a bearable MIL should that ever be the case.
Meanwhile, enjoying shoving in another load, being part SAHM (although DS is 9 FFS!), part PT teacher, part slovenly housekeeper with occasional flashes of (probably cycle-linked) vim and vigour and part (actually mostly) general volunteer...
DH picks up my dirty clothes from the floor, I wash his. He makes the bed 'cos he cares. I don't and if he's away I don't bother. I shop, cook, clean loo, and organise EVERYONE. If he's bothered about a household task I haven't tackled...he knows what he can do -eg. it himself. That's what works for us. OP has it sussed for her family.