In each other's youth, there were only him and her.
When she was young, what she always wanted was for the two of them to go from school uniforms to wedding dresses; from high school to college and then both of them entering society, she was no longer willing.
I don't know if he is making up for his own regrets or hers. After they separated, he started to fulfill his promise to her, but she didn't need it anymore.
This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.