I read this book and found it very thought-provoking.
My H was unable to attach due to his CSA/FOO and that was a large part of what lead him to his A. The one piece that could potentially have overcome the "perfect storm" was if he felt well-attached to me, IMO. Also, I suspect on some level he was searching for something to ease the pain of not feeling attached, although he did not allow himself to feel attached to OW either (thankfully).
He is so much happier now that he has felt safe to go there, and I can feel such a difference in our interactions. Of course there is no way for me to tell if he is as attached as is possible for him, but it is a profound change.
We are taught not to "need" others. OTOH, I do feel that I am complete in and of myself, and think that it is healthy. I "need" attachment with other people, but not in a desperate way from one person only; that could set me up for settling for less than I deserve. My H, however, has needed to learn that it is okay to trust and rely on another person, having learned the exact opposite as a child. His learning that "needing" another person and feeling vulnerable does not have to mean setting yourself up for betrayal has been huge.
On a side note, during my last IC session my C was commenting on how she felt that without the CSA there likely would have been no A and then she added that, in her experience, most As have nothing to do with the M and stem from something in the WSs past. I found that refreshing since some people report here that their MCs are all about "fixing" the M rather than focusing on the A and the way the WS got there.