I spent the whole series wanting to strangle Sylvia! How can someone be so consistently horrible?!
I spent a lot of time stewing over this. Sylvia at the beginning thinks she is pregnant by her married lover and snares Christopher. This is wrong. But given the circumstances of the day one can at least see the rationale. Once married it is plain that the two are incompatible. Today I think they would divorce. She then sets about to try and get some sort of reaction out of him (damneer ruining him in the process).
In ep4 she admits to these faults. She, like many, acted like an idiot. The backdrop of the suffrage movement is, I think, meant to emphasize that women at the time did not have the freedoms of men - and thus Sylvia uses what tools are at hand to try and stay afloat. I warmed to her, much as I did to the mother in Ibsen's
A Doll's House. Something like 'walking a mile in another man's shoes'.
I have been on a mad tear lately with these period pieces, and the thing I keep thinking is that these rich people need to get some perspective. Why not get a fricking hobby? In Parade's End we have a World War going on and these rich folk are nattering about their love lives...