My Wife is the Student Council President

The story starts with Izumi Hayato running for student body president. But when a beautiful girl swings in promising the liberalization of love while throwing condoms into the crowd, he loses to her and ends up as vice president. At the student council meeting, the newly elected president invites herself to Izumi's house, where she announces she will become his wife, thanks to an agreement their parents made, a drunken promise from decades ago that their children would one day marry. Naturally, Hayato is against it, but Ui has the exact opposite reaction and even wants to live with him. Can the upset Hayato and the overenthusiastic Ui handle their school and married life while keeping it a secret from the other students? Or will the two never understand each other's feelings?