your parents set you up with isagi. yes, you are older than isagi, you are 20 years old while isagi is still 17 years old. and isagi is still in high school, after two days of your wedding

isagi just got home from school. and entering a house too big for two, he threw his bag on the sofa and lay down. you came down from the stairs and sat beside isagi

"Turns out I already have a wife, argh! Why should I get married when I'm still in high school?!"