My Happy Marriage, Vol. 9 (light novel) — Akumi Agitogi

Now married, Miyo and Kiyoka head to the Old Capital for their honeymoon and to visit the Miyakoujis, the storied head family of the Kudou line. While Kiyoka wants to make the trip as fun as can be, things get off to a rocky start when Miyo is accosted by a beautiful man with blond hair and blue eyes by the name of Eugene on their very first day of the trip...and he seems adamant about recruiting Miyo to his cause. Meanwhile, after the men of the Miyakouji family learn of the power of the Usabas, Miyo becomes the target of harassment... But can Miyo and Kiyoka’s bond as newlyweds hold up under all this pressure?