Yes This is also is a perfect theory. This might explain Jill saying this:
Like Bella and James both knew that James cheated on Bella after miscarriage
{ I don't want to talk about this word anymore} and when James felt guilty and decided to confront Bella, He might have saw Bella and Jill together comforting each other normally like girls in reality do but we know how close Bella and Jill are and maybe James knew that too and seeing them like this , He mistook that maybe Bella and Jill had something between them and he too felt betrayed [ though he might have betrayed Bella first] and this might have lead to fight between them but after miscarriage parents usually are not up for fights cuz they are almost sad and same here with Bella and James they didn't want to fight more and so he left the house for some time which turned into 3 Years. And this theory may also work here that James might be a soldier and that might explain him being away for 3 years. He might had the choice to return to his House but either he refused and stayed there or He went somewhere else. When Bella said "It was...Different" maybe she was trying to tell him that she was not being intimate with Jill. And we know how Bella's character is as of ep6. After miscarriage one's mind can go into multiple directions and not being able to understand the situation calmly and Bella herself thought that doing with this Jill might make others see it like they are in relationship ,that's why she asks for forgiveness. And her saying " how long has been that a man desired for me?" I guess that this quite normal for a married woman to feel. She needs love , support which she couldn't get for 3 years. That's all I can say.[/SPOILER]
