Long story short, DSD (10yo) and DSS (8yo) are being dropped off here later by DH's ex. The whole visit was arranged with short notice, and only briefly rushed past me, as DH knows I have been busy preparing Easter for our 3yo DS.
This morning, after DS had opened his eggs, DH asked where the DSCs eggs are so they can be set up for later.
I told him I had not bought any, and when he got indignant I said it's as simple as they're not my DCs, they're his, it's not my fault he's waited until Easter day, when no shops are open. Not my responsibility, but as per usual, I've been cast as the wicked stepmother - happy Easter, hey? 
AIBU