My theory is:
The 2 did know each other in high school (even though she has no recollection of ever meeting him). He was trying to fit in with the “humans” and she caught his eye because she either treated him differently compared to the others (which is what he said when she asked what made him fall for her) - which I think means that his memory altering powers don’t work that well on her, and 1) this isn’t his real appearance and he simply adopted the physique of a conventionally attractive male which she didn’t fall for and this therefore piqued his interest, or 2) she found out that he’s not human yet still treated him the same way she would treat any other human and this made him fall for her.
Either way, he’s incredibly suspicious and not a very reliable narrator. We can’t trust anything he says about his or her past, but one thing for sure is that he’s head over heels for her. He’s most likely an otherworldly creature who’s on earth for a mission of some sorts and happened to fall for her.
The title is cosmic horror. He is not just an otherworldly creature. He is the type of reality breaking creature that will bring the end to a universe. LIke Cthulu. The way humans pronounce Cthulu's name is only a poor approximation.
When she first heard his name and she got a headache. Hearing their true name can cause a lesser being to go into madness.
The scene where she looks into the ring? That's something too. I was able to find it when I searched a few days ago, but I can't find it now..
The book she found earlier? It may be literally spells and rituals that summoned whatever her husband is.
But I'm basing that last paragraph on a romance game with cosmic horrors lol.
Title should’ve been “I'm the first love of my step-son who is a year older than me and whose father I had a short-lived political marriage with despite him being old enough to be my dad”
Mb mb, should’ve turned it into one of those isekai titles: “I reincarnated in a spicy novel as the first love of my ex-step-son who’s not only a year older than me but he’s also my old lover from my past life and the only guy who can satisfy me as I try to avoid his father the careless yet somewhat funny manwhore Duke of the North with whom I had a short-lived political marriage with despite him being old enough to be my father as he’s somehow fallen for me too so I guess I'm stuck in some odd love triangle although it’s not really a triangle but more like my ex-husband can’t seem to get the hint”











AHHHHH FINALLY