To answer more fully - John was actively involved for the first four chapters or so. He and I agreed early on that we weren't going to blindly follow the original Literotica script. Rather, we collaborated on deviations from and enhancements to it. In particular, the "Parker/Becky" arc was largely of my own devising, although John wrote the final dialog for both that as well as the Melissa arc in order to keep things consistent. (My words in Parker's mouth tended to sound different than his words in Parker's mouth, so we opted for his, since he is/was a better writer than I am.)
Unfortunately, life got in the way of his continued involvement. I'm still in touch with him off and on, and he's indicated that he's not dissatisfied with where I've taken the story since then, but since then it's been all me. (Plus, of course, all the input I get from people on this thread, patrons, etc.) Thus, if the first four chapters are awesome and the later ones lame, it's all my fault. To the extent that anything I did is good, it's largely because John put things on a firm footing early on, and because of the hours of chat time we had working out character details, motivations, etc.