The layers of complexity have been piling up since a while, this manga is very well written with both characters longing for warmth in their own way.
I'd like to point out that if these girls hadn't issues connecting with others we wouldn't have got this story to begin with.
Koyuki is really bad in approaching people and being able to read the room, she sees the world too much black and white for her own good, and like in this chapter, especially in Japan, this way of living your life can leave you with shallow relationships at best since people are going to distance you once they figure out this.
Konatsu is able to connect with others much better than Koyuki but wants to feel special (remember her sister?) since even when you're able to be in good terms with a lot of people, clicking with someone is really hard.
Their relationship, in a way, saved Koyuki because she was so lonely that even though she seemed fine all the time her family was and still is constantly worried about her leaving her comfort zone.
Konatsu at some point figured out that instead of a normal friendship
she had developed a codependency. Koyuki was doing great, for the most part, and having Konatsu always there for her helped her take that one step forward she needed.
Being fully aware of her feelings, e.g. wanting to monopolise the Koyuki, Konatsu decided that it'd be best to stop being this way since her wanting Koyuki for herself would also mean gold-caging her.
It looks like she's finally able to confront Koyuki now, I'm curious to see where this will lead us.