Totally MHO and nothing more: If he is a narcissistic sociopath, then he regards people around him as opportunities to do his bidding or obstacles to be removed.
His wife would be the perfect opportunity because she's totally dependent on him for support. He can force her to do his bidding.
Even if his true motive is revenge for loss of status and power, he can manipulate her into believing that he's been terribly wronged by his conviction.
He lost his job and his law license. How is he going to pay the mortgage, etc. He can make her see that Hasse and the McClellands have to pay for this injustice to him.
He might have even hoped to make her the patsy for the killings and he gets away with cold-blooded murder.
Very creepy.
If he is a sociopath, I think it's possible that EW will never confess. (like Scott Peterson). I just hope that LE has physical proof positive of his guilt & not have to totally depend of his wife's confession.
I'm also curious about how a married couple goes about planning 3 murders. Do they make plans over their morning coffee or do they make plans while engaged in pillow talk? Just crazy!!!!!!!!!!