So basically Rika was looking for a guy who only gets hard with her,not with any other woman and also gets hard if she have sex with another man(only one person who is like that)but shiratori didn't get hard after finding out she was going to be with another man which rika already imagined it that's why he got rejected. She must have fucked with all the village's man to find her true love hence the whore's house
-From the looks of things, that seems to be the case. Which is why it doesn't bold well for Akiba. Even if Rika loses in the end, divorced by sousuke. He would have ED and can't have sex with Akiba unless he watches momonga videos of Rika. Which would be demoralizing for Akiba in her relationship with Sousuke....unless she is into that kinda kink. She is a pervert who liked to watch affairs of the other PTA members after school. Or helps him redirects that, hard on only for Rika, to a hard on only for her.
-That definitely closes the case of why Misato commented she is the "whore's" (Rika's) friend. She sure got around during her college days looking for her "soulmate". There might be a psychological reason why Rika preyed on Sousuke for marriage in college, that will be monologued by her in the final arc.
Sousuke from the beginning was a Naive, trusting, and loyal guy who was content with his marriage life (maybe life in general).
Rika from the beginning is a textbook narcisist who lies, sleeps around, lives a double life, manipulates, and is very greedy with wanting it all in life. Sex (adultery), money (Secret accounts), and power (controlling people through coercion).
- As said by both Iwabuchi and Misato, after marrying Sousuke, Rika went off the grid and only contacted them recently, meaning she spent years without contacting them. Worse, Iwabuchi learned about her because she was doing Momonga with Shingo, meaning( as well) that it's been just a few months since she returned to their lifes;
- Something that came back was how the work treats both protagonist and antagonist in each arc. Sousuke always ends up with an insight, some growth, but in a worse place than the one he started with. Rika always loses something or someone, but manages to escape and goes one step further in her big plan.
-I think the reason she went off the grid was because she and sousuke were busy raising their daughter. Only once she didn't need as much care, Rika started finding prey to start/continue her business or "preparations" to mold sousuke to her liking.
-It's not known if Sousuke always had ED (only able to have sex with Rika) or he was normal until Rika sent him on his revenge quest. The further Sousuke went and got "revenge" on Rika's lover(s), he ended up in a worst spot psychologically. Despite Rika's business partner's being dismantled by Sousuke, it always seems like it was part of her plan for him to do so.
While everyone underestimated Sousuke from his apperance, it seem's like she was aware of what he was actually capable of and why she picked him for her "soulmate". Of course, Akiba did tell her she is "underestimating" Sousuke. Might find/get clues later on that supports this view or not.
Oh, and I also think it's safe to say that this chapter confirms the baby in Rika's womb isn't Iwabuchi's. Since Rika still belongs to Sousuke, Iwabuchi presumably still can't get an erection. That also answer why Iwabuchi looked so irritated when Rika said about Sousuke and touch her belly in the car on the way back from Rika Hometown
-This also shows that Rika would have no qaulms of getting pregnant from another man before marrying Sousuke. So highly likely if Iwabachi could have had sex with Rika then and there. Sousuke would have been raising a daughter that wasn't his own. Which what I know some of us, including myself, were suspecting.
-Which also puts one of the momonga videos of Rika "wanting to be pregnant from another man" in mind. That would have made Rika's marriage life (for her) more exciting. To see her husband raising another mans (Iwabachi's) child and whether he will find out or not. Or she knew Iwabachi was a man who wouldn't be able to perform with another man's women and she confirmed it that day. Which is ironic that he can't have on-going affair with her, despite his love for her. While Sousuke can continue to have sex with Rika (Even though he initially didn't want to), despite her affair.
So who was Rika having sex with in the video Sousuke saw? Was it Sousuke himself, who was drugged?
-This chapter revealed Iwabachi isn't the father and Shingo isn't the father because he claimed they were careful. Unless there is another secret affair partner that I missed or will be introduced in the future (it's way to late for that)...Rika's claims that Sousuke is the father is true. As for the conception, Sousuke (as well as Shingo), always used protection and were careful from their knowledge/testimony.
Either Rika is actually lieing about being pregnant and faked the ultra sound (For control), or Sousuke was drugged and lost his memories of doing it with Rika without protection (Possibly for a momonga video she posted later for clicks, Titled "Impregnated by another man that is not my husband."). That is just my theory.