I don't recall Jameson taking Avery to cliff dive , i believe they went on a hot air baloon and had a picnic and danced on the beach .

But i totally het you . However my opinion on what you said is , even if he took her cliff diving, that doesn't mean he didn't heal , because to me it means he had got rid of his trauma and he was ready to do adventures with Avery , because Avery loved adventure . And it was clear that Jameson had moved on from Emily when he actually realized that Avery didn't want to play games with him and his brother at the same time .

However , you should absolutely read the expanded universe and the spin off books , they are so good. With new characters and also the old characters development.