the guy need to realise that she's far away from him (from MC's point of view), and he need to get socialise and move on. i hope one day the MC will have a woman friend to come over, and how she reacts.
i know this manga is about teasing, but i really hope that one day that the MC brings his new girlfriend to his room, while mika-tan is forced to watch him having sex with new gf. Experience the despair.