A world of pure love starting from a book

Xu Fei accidentally obtained a system that can travel through various worlds of Hentai. What he has to do is to change the tragic fate of all the heroines and give them a new life...
This book is more realistic, so there will be some plots in the book. People with mental obsession should be careful. This is a hentai, please do not use the world view of the hentai to substitute.