i believe this is implied to be a sequel to
A Thoughtless Reply. note how both girls have bluntly cut strands of hair on the sides of their faces. both guys also keep going on about how "their" love will persevere in the face of social class prejudice or something. the guy's hairstyle change from slightly wavy to straight and gelled could be justified by an explanation that he styled it for "their" formal wedding.
also assuming that Ghost Marriage girl is the same one from Thoughtless, she should be muttering "Master...?" instead of "Dear...?". in the raws, the girl from Thoughtless called the guy 坊ちゃま (bocchama, "young master") at first as a affectionate formality when they were younger, but when they got older and the guy stated invasively pursuing her, she started using the more serious 旦那様 (dannasama, "master") in an attempt to create distance. the Ghost Marriage girl also uses 旦那様 in the raws, presumably in continuation of this habit.
i feel its interesting that, presuming they're connected, the author tried to continue the supernatural stuff between Thoughtless and Ghost Marriage. i still don't really like how it's not really explained, especially the talismans covering the guy's eyes at the end of Thoughtless. personally i have the explanation that the guy knows all these dark spiritual techniques because he found records of his old wealthy family having used them in the past in a musty storage room while trying to find out any methods possible to have the girl forever.
also damn. she killed herself to get away from him, but his yandere selective perception assumed she was trying to escape being persecuted for "their" love. the guy also talks big about going against society for love, but from a certain point of view, he's only getting away with doing all this crazy stuff towards a woman because he's a man set to inherit the wealth of his noble family.