Big balls on Kai for shutting both down, their deal about sharing his life to Akira was huge invasion of privacy
Kai should have told Shion sooner about the deal between Akira and him in order to distance Yuuto from Akira, she knew something was off, shouldn't keep her in the dark.
Don't think Akira will go stabby on Kai, her backup plan was going after Yuuto and be closer to Kai in the process even if she married him... girl needs someone strong enough and professional help along with moving the FUCK out of her mentally ill mother.
Thanks for the scanlation!