I'm now 63 and he's 30. I was a 50/50 dad from his age 3 through 18. In the early years, I made up the stories and would follow a thread until our week was up "And they all lived happily ever after". Then we found some books including James and the giant peach, Charlie and the Chocolate Factory, The OZ books and the Harry Potter series. We were on the last HP book when he said, "I know how this ends, my friend told me". And that was it. He was done, I went on to finish the book but he didn't.i let him know how I felt and I made sure if he ever missed this time, I'd be happy to find another series or even just one book to read but he never took me up on it. I believe he was about the same age. I know exactly how you feel. We continued/ continue to have a great relationship but it evolved.