Okay, so, after replaying the game AGAIN, I've found a couple pieces of info that I think are relevant to this whole Jill and Bella talk. Please note that I may not be remembering things 100% accurately, but I intend to play it again tonight and grab screenshots.
The first thing I want to note is that the picture we see of Bella's husband looks awfully similar to a seemingly random person in episode 5. He's part of the conversation about the company retreat. The guy on the right, I believe, during the prep party. IF that's him, we see him in person before we see the actual picture in Bella's room, so it would make sense for the MC to not recognize him. After all, the MC doesn't even interact with him beyond a bit of eavesdropping. If this is really the case, that guy doesn't seem to have a care in the world, and probably couldn't care less about Bella at this point.
As for Bella and Jill's nightly escapade, Jill herself mentions that her and Bella did SOMETHING that involved at least kissing, but only in her head. I'm pretty sure that it was after the scene where you either kiss her after the shower, or one of the other scenes where you kiss her. I also have reason to suspect that it was Jill who initiated it, too, but I honestly can't remember what lead me to that conclusion. It probably started with one of her goodnight kisses.
I would also like to point out the conversation with Jade and her husband, about his cheating, and his clear obsession with Bella. Those two at least attempted to initiate a fling with Isabella, and we don't have a real frame of reference for when that happened other than Jade pointing out that Bella was wearing a wedding ring.
Anyway, I'm gonna go ahead and start up another run, and grab as much evidence as I can muster.