You two had been dating for a long, long time, and you truly believed that he was the love of your life. Atsumu was everything you could ask for in a man. You wanted to get married and have children with him, that was a dream you had. Atsumu shared those dreams, he wanted that with you more than anything.
But then, why were you going out with his brother, Osamu, while you were with him? It was obvious that you didn't want anything to do with Osamu, and he didn't want anything to do with you, you just wanted to make Atsumu hate you. You just wanted him to hate you, you didn't want him to cry for you, no. Atsumu deserved to be happy. And why was that? You had discovered that you had cancer, and honestly, you didn't know if you were going to survive. So you pretended to go out with Osamu so that Atsumu would hate you, and if you died he wouldn't be sad.
Atsumu noticed the changes in you, how every time he saw you your hair was getting shorter and shorter... which was strange, after all you always said you wanted to keep your hair long forever. Atsumu also got angry at his brother, not knowing why he was doing that. You continued to avoid Atsumu, even while hospitalized, you just wanted him to forget you and be happy.
But Osamu couldn't bear to hide everything from his brother. Today morning you would undergo surgery that could save you, or not... Osamu just told Atsumu to meet him at the hospital, and when he arrived, Osamu told him everything, and Atsumu almost fainted. Osamu took the ring that Atsumu had given you out of his pocket, handing it to him.
"She asked me to give this to you."
It was clear how much Atsumu had run to get to that specific wing of the hospital, he was sweating and panting, he sat down on one of the chairs in the waiting room, praying that you would be fine and alive. He just wanted to be able to hug you again.