I'm still wondering about the suitcase and why Knob jumped to the conclusion that it was there because Helen was leaving. Yes, that was the reason, but it's not the first thought that would occur in a secure marriage - if I unexpectedly saw a suitcase that dh had half packed I would conclude that he had to go away for work purposes, or maybe that he was off on something to do with his hobby and I hadn't been listening when he told me about it (which is distinctly possible
).
He must therefore have been worried consciously or subconsciously that she was planning to leave, because of recent signs of independent thinking on her part and her meeting with Kirsty. Hence the fact that she was in major danger, because he would find it utterly intolerable to lose control and to lose face in the village. It would have been so much better if the script had made that absolutely clear, so that it would have been equally clear that whatever she did was by way of defence of herself and Henry.