Aoki's a pedo. He wanted Rin to love him.
The story just got 100 times more predictable. When a kid declares he/she will marry a relative, you know the outcome will be a fight between the original lover and the relative, then it will end with either a good end or bad end. Good end is where the original lover gets the kid, and bad end where the relative gets the kid and the original lover gets jailed/killed.
Not that I want the latter to happen, but it would definitely be funnier.