I’m a fan of her previous books.
A Times 2 article on this by Helen Rumbelow is good IMO. Alexandra seems to acknowledge, in her ‘darkest moments’, having felt ‘duped’ by her then H into having a DC, but then argues that he was ‘consistently not a deceptive person’. When the evidence v much suggests a long, long period of deceit.
It seems that she’s chosen to say mainly positive things to and about her ex, that they are a woman etc, and to seek to maintain a good personal and co parenting relationship with them. (The article said they shared residency of the DC). And to reject the idea of herself as a victim. Which is, of course, her prerogative - it’s her life!
The alternatives could lead to negative consequences from her ex, some of her friends, acquaintances, community (Brighton) and professional detriment too.
As PPs say, wondering if these choices have psychological costs.