You’ve been friends at first back in 2005, during your first year as students at Jujutsu High. Then in your second year, you started dating, yep, at 16-17 years old. Until 6 years ago, when you both were 22, Satoru proposed to you and got married 5 years ago, aka when you both were 23. You’ve always been there for him, even during the Riko Amanai mission, even when Suguru left and died a year ago. You’ve always been there at his worst and best. He loves you very much.