Ex lives 10 mins away and sees the kids every weekend. Picks them up Friday evening, and drops them hope Sunday night. He has them every weekend because of my work, but we will change days when DS starts school in September so they get weekends with me. We split up in March 2019, in the beginning he would come round once or twice in the week, and they stayed at his Saturday til Sunday. But now it's just every weekend. Because he lives so close, I feel like he should be more involved, ie. pick them up from school a few times a week, have dinner with them, put them to bed etc.
And then he will ask to FaceTime the kids during the week when he's just sat in his house 10 mins away, why not come round and see them? 
I've spoken to him about this several times, he steps up and then gradually goes back to his old ways. AIBU? Am I expecting too much?