ok guys i have my own theory about the story(up until now), i believe that yuki is the real author of the book, but for some reason she tells kita that is her husband, and in reality the one who calls her is an editor that is trying to change her mind about writing another book, and for the ring well... maybe the husband is dead already and the book is based of the things that she wanted to do but couldn't,
& for the girl on the street maybe a relative of yuki i guess she lived there at some point
well... we will know the truth in the next chapter i hope so we can see if indeed she have a husband or is using her name