Who have the power to kill have the power to choose to break or keep the deal, since the powers weren't equal at all, it was never a good idea to surrender.
I always though Wakaba reincarnated as a spider but she is "body double" and was a spider ALL this time? This is true plot twist.
edit: "true" Wakaba is an asshole narcissistic.
yeah, ignore your instincts and laid on mother, she pretends miscarriage, then daughter and be miserable because you feel guilt on touching daughter with mother there.
This is the reason why I hate start reading romcons or romance mangas, they make them LONG on purpose, not because of storywise. Sometimes I wanted these types of developments works like ero doujins