I was wondering kinda the same thing but what when she told the ogrinal in flasbacks "i curse u" or something like that it accually became a curse to the blood line and if he is a descendant well you get the point
Good theory. I actually really like that explanation.
I'd also prefer if he's not the reincarnation of the former king since that plot is overdone at this point (imho). It was already explained why he looks similar and it'd only be natural for her to have similar relationships in this life as she had in her past one since she's still the same person.
What if he's not a reincarnation of that man but merely a descendant and there is a real one who's gonna appear later Σ(っ°Д °;)っor maybe he's gonna remember later when the curse is lifted... Don't Spoiler me... I'm just wondering by myself