when Atsumu caught his fiancée cheating on him, Sakusa Kiyoomi was walking inside the mall with the blonde.
The setter froze for a moment before he walked away crying. He and his girlfriend was dating for 8 years, and he just proposed since she insisted. Atsumu was gay ever since but for him to feel loved, he did everything for this girl wishing to be accepted.
He cried all night inside his room, while Kiyoomi was comforting him.
When Osamu arrived, that's when Sakusa admitted to the Onigiri Miya owner, that for those 8 years, he was waiting for Atsumu... and he's willing to wait until the blonde realizes how he feels. Osamu bitterly smiled and said "He'll be happier with ya.. I just know it."