Hi Everyone! New member. My theory:
I think SW got home and CW was quietly fuming about the life he thought he could have with the new AP, probably younger, fitter, better educated, into him versus the life he was living. I bet he let her go to sleep as he quietly fumed and then between 3 and 4 in the morning, he straddled her back and strangled her from behind. I don't even think she was sleeping with him if she suspected him of an affair. She was probably sleeping on the loft couch. And knowing how it is with my toddlers, I bet those little girls were in the parents' bed. He probably straddled her and strangled her from behind on the couch and she couldn't really fight back from that position, maybe a couple of scratches on his hands and arms and that is how her phone got stuck in the cushions. I don't think it was preplanned much further beforehand. He probably strangled the kids while they were sleeping in the master bed (why the sheets were stripped because they wet themselves). He knew that no one would ever believe that SW would disappear without the girls.
I think after he killed SW, he thought it was best to say she had left with the kids, so the 2 little girls became his victims to save himself. I think he then had to come up with where to dispose of them and this is why he did not have time to set up the crime scene before he left. He probably thought he would have time to get rid of her purse, vehicle, cell phone later in the day, never thinking that one of her friends would call the police so soon.
I think he decided on the oil tank because he thought they would all fit. I bet at his chosen site, it took time to get the bolts for the hatch undone. I also think this is when he lost the sheet wrapped around SW or the kids. He couldn't fit her body in there with the sheet on so he unwrapped her to try to get her in, or he took one last look at his kids (if it was wrapped around them) and it blew off while he was on top of the tank.
Because SW did not fit in the tank, he now had to try and attempt to dig a grave, which gave him zero time to look for the sheet. Of course, he probably thought he could come back later to really get her in the tank.
to me, everything seems like it was done in haste, with little forethought and he has been reacting, but all his reactions are done halfway and look bizarre. The whole story is crazy to us because it is so haphazard. I think he killed SW and went in CYA mode and made horrific choices.