It's definitely the beginning of the end now. Let's look at the evidence:
- Rob has hit Helen after she called him a bastard (she saw the light, albeit very briefly). That's a big turning point.
- Rob is sending Helen for therapy, seemingly without realising she'll be seeing professionals who will have doubtless dealt with similar situations before and will know the signs
- Carol has been added to list of people having their doubts about Rob and it's being discussed openly (again tonight). If that wasn't significant they wouldn't be mentioning it.
- Helen isn't that far from giving birth and I still don't think the baby will survive. Depressing, I know, but I think that'll be the end of the storyline as I think Rob will flip and do something drastic because it'll wreck whatever he's plotting.
One interesting thing from last night's episode is that it proves Rob knows exactly what he's doing. Previously people have been wondering if he actually believes what he's saying. If he does, it'd make him scarily unstable but at least he wouldn't be seen as scheming. However, last night they let us hear exactly what Helen said while sleepwalking then let us hear Rob completely lying about what she said. Again, another development, as it shows he has some sort of plan.
Henry's honesty made me laugh last night, though. When Rob was trying to imply Henry was really disturbed by Helen sleepwalking and he said "I was all right" in an unconcerned fashion.

He will no doubt pay for not being obedient now... DUN DUN DUN!
God, I hope it ends soon. It's really dominating the programme now, not because it's gripping or exciting but because it's sapping the life out of everything else.