CW seemed to be such a good liar, looking one straight in the eye, I would say he has been a liar for years. Perhaps a spontaneous liar (can’t think of the name!).
Remember when he met Shanann, she was in a dark place and he could be the savior with patience and guidance to help her. IMO, he could also manipulate and tell her what he wanted to - truth, lies on who he was or what he was doing.
My opinion is he has always played her. She finally woke up as she grew up, came into herself as a mother, made friends, started her business, and realized she was a real person who was loved, valued, and successful for who she was and her illnesses didn’t define her.
This was the worst thing that could happen in the marriage! It scared CW to death! SW was now a real person. She was out and about and would see how other wives and husbands interacted. She would eventually wise up to how different her marriage was. Little by little, SW would figure out the lies she had been fed all her married life.
My opinion only.
I do think CW played SW from the start. I also think she did figure this out before he murdered her. I wouldn't be surprised if she kicked him to the curb and he murdered her and her little girls to get even with her. JMO.