You know, I'm having trouble again believing CW that SW put him into a rage. How? She was away for 6 weeks. She wrote him a love letter. How can you put someone in a rage when you are barely even around?
He was acting suspiciously due to an affair. ANY spouse would be upset, paranoid, hurt, etc. Being emotional and argumentative is typical when you are realizing your partner is lying to you and betraying you. She was probably confused because he kept giving her false hope and then acting cold again. She was pregnant, working, raising two toddlers and getting NO emotional support from her husband. And to realize another woman is the reason why you're distant and cruel?
But back to my original point. How could she somehow push him into killing her when she was hardly around to push? I doubt she said much to him that night. I bet he was cold yet again and she cried herself to sleep alone in the bed before he ambushed her and killed her. Just my opinion.