MC asks Iida what she thinks of him. She takes him outside, they look at the stars and she gives a speech about how she loves watching them shine but from up close they are just gas and dust. That's why she prefers looking from afar and asks MC if she's still shining. MC says that he loves her but gets no answer. After getting encouraged by the blond girl he asks Iida again and she agrees to go out with him. She tells him that she doesn't know what it's like to be in love but he is special to her. Things get awkward when despite repeated attempts he can't perform well in bed which results in Iida feeling pent up. Blonde girls tries to get back with senpai and asks Iida to go meet him with her. MC notices them at school and goes to the toilet imaging senpai fucking her bc she was so sexually frustrated. Meanwhile senpai starts getting it on with blonde girl and asks FMC to join them. In the evening MC meets up with her and asks about what happened there. After some hesitation she says she had sex and my dude THANKS HER (seriously) and breaks up with her. He realizes that seeing his idealized girl being dirty and defiled is what excites him, not being with her. Oh and the blonde girl want to go to the same university as senpai and says she'll let him sleep with her if he helps her study (this happens after dude asks FMC for threesome and yet she still simps for him). 6 years later MC is salaryman and meets with IIda working in the cafe. Just like in the hentai version, MC keeps in contact with her all these years so she can tell him all about her sex adventures and ends up saying that she'll fuck cafe's owner later this day because his wife left him. After MC leaves, owner closes cafe... and his wife walks in all happy. Flashback to the senpai asking her to join for threesome, Iida refuses and walks out, saying that she has someone special. Back in the modern day, both of them think happily about each other from the school days and say thank you.
So, about the ending... I feel like the speech about stars is the most important part. They shine from distance, but from up close they are completely different. At first it looked like it was refering to MC's feelings about Iida, but her lies in the ending make me think she was talking about her own feelings as well. MC was her high school crush and it is strongly implied that he still is. Even so, dating was making things between them worse so she decided to lie and end it. Then again, nowhere in raws is mentioned why does she know that MC is getting off from NTR and why she keeps lying about fucking around to make him happy, so i might be mistaken about something. Tbh, it feels like the relationship between them could work if both of them just talked about their needs and wants, but of course this is manga and nobody ever does that here...