A very interesting read. Just want to add my 2 cents.
Fully agree about how Edwin created a narrative in his mind about Vicky being a martyr and how Donovan's videos are destroying it, making her look like a whore rather than a martyr. Now there is also the matter of selling the house. As far as I remember, after Edwin's father's death they weren't on brink of poverty, Vicky did porn so she could keep the house. And her decision to sell it now basically nullifies her sacrifice. "What was the point of going through all of this if you are going to sell it anyway?"
The dates of the videos thing feels far-fetched though. As i said, they weren't on brink of poverty, Vicky had a job and, most likely, some savings. She didn't need a new source of income immediately. Thus, her entering into porn industry only after a while since her husband's death doesn't look suspicious to me.
Also can't agree with the 'theory' part. As I see it, Edwin as a character has this vile, sadistic 'core' similar to Kathleen but after he sees Vicky in tears Edwin builds a shell around the 'core' that suppreses all the deviant tendencies. The shell of being a good, virtuous man. And later, after discovering his mother's past, uses the narrative to strengthen it. The narrative is the vital part of this shell and without it the shell will collapse which will expose the core and turn him into male version of Kathleen (which is exactly what Kathleen wants as she can sense sadistic nature within Edwin and wants to have a kindred soul around her). This is what Edwin is afraid of and tries to prevent, imo