Since September me and my ex have been doing 50/50 with our two sons (7 and 14). We do a week on week off. On Wednesday whoever is not with the boys for that week will pick the youngest up from after school club (5ish), bring him home and all 4 of us have dinner together.
Its my week this week and there is a winter festival where we both work. I had forgotten about it until this morning and I asked the kids if they wanted to go. They said yes so I texted my ex and asked if he wanted to come with us. We will be home by 4.30. He's now kicked off because he was looking forward to picking the youngest up at 5. I accept that I should have checked with him first but it feels like he is going really over the top. AIBU?