For those confused about the ending

With the exception of the ending I think everything was real. We can see the impact that David had on Margaret’s life. Due to him completely ruining her trust with men it means that she’s having sex with a married man. That makes him off limits as far as relationships go. It’s also why when Abbie invites him over for an intervention that she’s so pissed. Because it’s just supposed to be about sex and nothing more. The same goes for when he tells her that he loves her. We also see this when David asks Margaret who the father of Abbie is. She says that she just had sex with random men, so she doesn’t know who it is. She did that so that she could have a child and the father wouldn’t be involved in their life so that she wouldn’t have to experience what happened with David and their son again.

David obviously never ate Ben. He killed him and and then buried or put him elsewhere as part of the abuse. In the same way that some people will try to have a baby in order to keep their partner around, he decided to kill the child and convince Margaret that he ate him and that he’s still alive inside. It’s obviously insane, but you have to remember that when Margaret told Gwyn about their relationship that she mentioned that she believed everything he said. So for as unbelievable as that is, she still believed it because of how successful he was at manipulating and grooming her from a relatively young age.

The end I believe is her breaking out of the delusion that she went into after killing David. We already know that Abbie moved out their apartment, so it makes no sense for her to be packing up. And Ben has obviously long been dead. So we get that zoom in on her where everything looks perfect. Except it keeps zooming closer and closer revealing all the flaws on her face. It’s her delusion slowly breaking.