We Got Married at 18

The main girl wants nothing to do w/ love as she sees her whole life the ugly unraveling of her parents' marriage.
One day, she meets a tiny person (dwarf-size w/ human characteristics) in the rain. It turns out that he is the librarian of heaven going to Earth to find a book that records humans' love connections and his punishment of losing the book was turning tiny every time water hits him. He is a member of a famous and very popular idol group for it makes it easier to find the book.
It happens that her younger sister showed her that book a few days ago thinking that it was a "fan service" for it has all the members of the group mentioned and their life partners.
Her younger sister fixed the book which is intertwined with the book of life.
Now everything is changed and 3 girl lives (the main girl, her sister, and the female member of the group) are at stake!
A manhwa with supernatural, virtual games, and the celebrity world.