either is fine, thank you

While I too think it's a plot device to lengthen out the story

I think the only plausible reason Jinha isn't telling Siwon is that
>tells Siwon
>Siwon understands and stays away from baddie
>baddie boy is like damn you know now, now I can't have my fun
>baddie does crazy rich guy bad stuff and possibly hurts Siwon (which we know Jinha wants to avoid at all costs)

Maybe he's overprotective to that extent, that he doesn't even want to tell Siwon bad things. Like a parent refusing to tell their kid about the harsh reality of the world.
Yours is plausible as well.

Exactly, ifwe consider the first translation it was like Shirotani said that Kurose wanted someone else, after something like that there is no way they could continue making love like nothing happened

I know, right. So strange. I even felt like "oh no, I don't like Ten Count anymore" with the first translation but was all hyped and in love with the second one.

Same!