Manga by author Yokoyari Mengo

From MangaHelpers: 17-year-old Awaya Mugi and Yasuraoka Hanabi appear to be the ideal couple. They are both pretty popular, and they seem to suit each other well. However, outsiders don't know of the secret they share. Both Mugi and Hanabi have hopeless crushes on someone else, and they are only dating each other to soothe their loneliness. Mugi is in love with Minagawa Akane, a young teacher who used to be his home tutor. Hanabi is also in love with a teacher, a young man who has been a family friend since she was little. In each other, they find a place where they can grieve for the ones they cannot have, and they share a loneliness-driven physical intimacy. Will things stay like this for them forever?

From MangaHelpers: When the two were still young, Saito and Kawana Subaru were close friends. But with Subaru coming from a wealthy family, she was sent to the top school while Saito had to settle for a regular education. But after painfully studying for years, he was finally accepted as a high school freshman through a scholarship program that only a handful of students are awarded. But what Saito thought was going to be a heartwarming reunion turned out horrible. Subaru had grown up beautiful and was the most popular person in school as she was kind to everyone, all except towards Saito who she seemed to despise. Almost regretting his decision to come to the school, Saito wishes that somehow their dorm rooms would connect to each other. Magically, because it turns out that Subaru wished the same thing, their wish comes true but, in return, Subaru loses her self-control for one hour per day. During that time, her erotic desire for Saito, that she can normally hide, comes pouring out and her true intentions are revealed. He wants to take advantage of this once in a lifetime chance but doing so might jeopardize their relationship during the other 23 hours.

As myriad seasons make their rounds, The scars of the past turn to memories. The spin-off serial of the painful and forlorn "distorted love story" has begun!