DH and I both work similar hours and earn a similar amount. On balance we do the same amount of childcare to fill the gaps in each other's schedules.
I probably do more cooking and laundry, but he does all the house admin and DIY, so I guess we're pretty even in that regard.
BUT, on the days he looks after our two DCs (one toddler, one primary age) I come home after work and the house is a total shithole.
On the days I look after the DCs I still manage to get the basic stuff done like stick a wash on and hang it out, unpack the dishwasher and bung the dirty breakfast stuff in it, wipe a cloth over the kitchen surfaces and make the beds. Even open the damn curtains in the bedrooms!!
For some reason, under exactly the same circumstances, DH is incapable of doing any of this.
So I come home and am immediately pissed off because I have to spend the first half an hour either corralling him into tidying up, or doing it myself.
He thinks IABU because he does such a great job with the childcare.
I think he IBU for not managing to do a great job with the childcare PLUS all the stuff I do too.
But I'm aware that if I were a SAHM and my DH came home from work ranting about the state of the house, I would tell him to stick his attitude right up his bum.
So AIBU to get irritated with DH?