I think she is doing as she believes right - although her emotions are engaged by Edward's changed behaviour, she is not allowing them to overwhelm her and instead is behaving rationally. There are two sides to this. Firstly, in terms of their relationship, she is regulat[ing] her behaviour to him by the past rather than the present: ie not changing her view of him on one instance of behaviour against how he has been for longer periods in the past. Secondly, in terms of everyone else, she is not showing her feelings or discussing them, any more than she did in the past when she was falling in love with him.