Honestly tho for me personally, the pedo sensei's so called "true feeling" prob just because he is so used to mc that the bitchy twin he was chasing becomes something he doesn't care for anymore.
And after months got back together the pedo guy starts beung indifferent and then mc got out of the relationship and find another guy in much more wholesome scenario. And later when mc got job he becomes successful and the asshy twin after taking over whatever the grandma's bizniz is, he failed it and goes bankrupt