If so then good, when chapter 9 is released and it's translated as you mentioned, then I'll retract my comment. But for now I'll leave my comment as is until I have definite proof.
Dude if you literally can't read Japanese don't pretend you know what's happening in the chapter or the story in general. You're just looking at pages and interpreting everything in your head which obviously leads to wrong conclusions. At least preface your post with "I think this is what's happening" instead of shouting your theories like they're fact.
I've read the whole thing and literally nothing of what you said happens. In chapter 9 they're recording an intimate scene for a regular movie, you can even see the director yelling "cut" (カット if you want to check the page in the original) before they do anything explicit, which obviously wouldn't be the case in porn. Why would she even do porn when she's a famous rich actress? She wouldn't have an acting career if she did that.
There is no ntr or hints of it, and she does not sleep with anyone. Only the protagonist has sex and it's in front of her. And she has made it very clear the only thing she's interested in is seeing the protagonist have sex with women he doesn't even love because it gets her off seeing him use other people like sex toys.
Fine, don't trust me if you don't want to even though I know Japanese and have translated various manga on this website to show for it, but don't tell other people stuff you don't know either. You're just spreading misinformation for no reason.