There is also one detail from the beginning, when Yuni chan slapped Fuuko, and Fuuko says:
"Compared to the kiss we had, or to the kiss THEY had, I definitely felt more honesty and passion from Yuni-chan's slap"
https://dynasty-scans.com/chapters/my_girlfriends_not_here_today_ch06#30
Fuuko saw their kiss and took the pic. She noticed a lack of passion between Nanase and Yuni. It gave her the additional reason to act and start to conquer Yuni.
There is also a situation when Yuni had sex with Fuuko, and she is rubbing and touching her and she compares how she felt Nanase and Fuuko separately.
Nanase was toned, and Fuuko soft (to touch, but there is a possibility that it was about their characters too, one rigid and closed, one soft and open)
Yeah, Nanase is very stiff and strict, not so generous to touch Yuni.
And Fuuko is very open to touch her.
Reading again all these old chapters, the problem with Nanase is transparently obvious, isn't it?
The teen years are a time of lust and passion. Fuuko acts like a typical teenager in love: she wants to touch her loved one and do sexual things. Nanase? The only thing she wants to touch are volleyballs. Where's her libido?
And...we should not forget that Fuuko did not answer Yuni why she loves her, they were interrupted by forceful entrance of Nanase.
She literally entered, grabbed Yuni like her possession (and Yuni liked it!) and took her away from Fuuko.
I wanted to hear the answer so badly... but I guess the writer wants to keep us in suspense lol. It most certainly is an important plot point.
There are situations left open, there was no real closure between Yuni and Fuuko.
This is probably what bothered me the most in this chapter. Yuni acted as if Fuuko wasn't there. Even if she decided to follow Nanase, she shouldn't have ignored her like that. It really made me mad. >:L But the writer herself admitted that Yuni was "everything annoying in a woman" rolled together, so this kind of attitude comes as no surprise.
And there is real question how the sex between Yuni and Nanase will happen and what it will look like?
Is Nanase capable to give Yuni the passion she needs?
Can it change "overnight" from complete disinterest by Nanase into mindblowing sexual passion between them?
If I'm reading the story right, Nanase hasn't even gotten the point yet lol. Right now she's thinking everything will be fixed with more attention, dates, gifts and compliments. She still doesn't understand Yuni's frustration at all.
It would be great from author to show us more "skin to skin" events between Yuni and Nanase, that we can complete the pic.
There were only vague flashbacks of sexual exchanges between Nanase and Yuni and not so passionate kiss exchanges. Really not much physical contacts between them.
Nanase never initiates anything (she doesn't seem to have a sex drive even though she's at the age of adolescence) and Yuni is the poster girl of passive-reactiveness (a total bottom sub who wants to be sexxed up all the time but doesn't say it because it's embarrassing). They are a very incompatible pairing.
Did Nanase really had a GF all that time or just called Yuni her girlfriend and was satisfied with it?
The latter. Nanase is like a character from a yuri manga from forty or fifty years ago: she thinks it's all about platonic feelings, looking into each other's eyes and sighing.
When she "claimed" Yuni in this chapter, Nanase acted so dominant and overpowering (I'm tempted to say manly lol) you'd think she finally woke up and saw the light. Yuni certainly seems to believe it. Me, I have my doubts. If Yuni expects Nanase to bang her on a regular basis from now on, I suspect Yuni is going to be very disappointed.