I think he acts like that because when the curse appeared he was still a child and everyone even his parents left him so he grow-up to fast so....... hes just goin back to what he was like before (=・ω・=)
I feel like they should have given more background on the seme Like seriously why he decided to kidnap a person he had never seen before and rape them then stalk them for the foreseeable future they kinda glossed over that
He was crying like 90% of the story