As much as I love the story and am very interested in what's happening, these two should seriously get some help. They're clearly not okay mentally and even if they see this as a form of happiness and like it, it's not okay for either one of them. If they want to have a happy ending there needs to be clear communication with their friends and between both parties, and they should also try doing healthier things that make them happy. Like, I'm actually getting worried for the both of them, especially Hina seeing as she thinks Ai's abuse is her own form of attention specially for her.