I watched the video on iplayer about this, what happened to her children was truly awful and them deciding to release him on bail to his home address which was opposite where they lived was a terrible decision given what he had done. BUT personally I cant condone what she did, I have 3 young children myself and I can't even contemplate how she felt, but I just don't think I'd be capable of such a thing. To murder anyone in such a cold blooded way you would surely have some sort of background where violence featured/have some sort of mental illness? I just couldn't do this, not just on a moral level, but I wouldn't have it in me to take someone else's life. She was charged with manslaughter, how she managed that when she set out with a knife is beyond me and she didn't call for help after she'd done it, definite intent to murder. She was lucky to only get 7 years.
Longer prison sentences are needed for the sexual abusers and no bail offered when they are arrested, the system did fail her and her children, but what she did was very wrong and deserved a prison sentence.