Totally support the direction in which you ware thinking...
In addition to 2, add that at the end of that scene, Bella takes her wedding picture from the nightstand, puts it on the floor and shoves it away. I would say this a strong indication that the scene we just witnessed has something to do with the problems between Bella and her husband.
Yeah, that's another interesting part of that whole thing, that after getting into an argument about something that "won't happen again" which they seem to have agreed to never talk about, she shoves the picture of her and James off the nightstand. If this was just an issue between the two of them, why would she feel the need to do that?
I know some people don't want to see this because they think it would "ruin" these characters to have had something intimate happen between them before, but if it isn't that then it's biggest the red herring ever and difficult to see right now what else would make the most logical sense when you put all these pieces together.
Possibly true. It could also be the case that she ‘blames’ her husband for feeling as though she can’t move on and be intimate with others. So while it could be connected to whatever happened with Jill it’s really more about her issues with her husband than with Jill.
One of Bella’s lines is something like “come back, I’ve already forgiven you.” Which suggests he is at least partly responsible.
But then if it has to do with her issues with her husband, then why would she throws that picture down if it was unrelated to the argument she had with Jill? It's almost as if, in that moment, she's lashing out at him because whatever happened between her and Jill has something to do with him.