You may be right, of course. However, I read the polygraph report. If you read it from the very beginning - and we know that by that time CW was taking the polygraph test, the family has been annihilated and buried in a bizarre way - you'd read "civil", "never fought", and the whole tragedy is minimized to a very polite discourse over an amicable separation.
SW wrote "love you" in her text to him prior to that fateful night, I think (my timing might be wrong, but shortly before - the one that he did not answer to). This is when the relationship already deteriorated to the extreme.
What I want to say, CW lied so much, he might have been projecting the image of a happy father and husband, while in reality he was deeply dissatisfied with the marriage and family. We can not make any deductions based on the Wattses' demeanour and behaviour. Plus, they were projecting the image of a happy family for the sake of Thrive sales as well. (Not being cynical - they looked like an ideal family on all photos).