CarryOnDancing The title and content make no reference to any preventative measures. So I don't see why it is 'sick'.
Having had a quick look, the book/chapters cover a lot of possibilities, the DM have just chosen this one for the sake of a good headline.
I don't see why anyone should be castigated for wanting to put back together a broken relationship. I really do not read it as a woman being told to right her wrongs. To me it is simply a list of things to consider should you want to win back your cheating OH. IF not as a directive, you must or you are a failure.
It also says nothing about what to do if your cheating husband wants to come back and you aren't sure that is what you want. It is only about what a woman would need to consider if she wants to actively stand up and fight to win her cheating husband back.
Read from that perspective, the one it was written for, and the contents make perfect sense. They may not be palatable in any way to someone who has absolutely no intention to forgive or fight for a cheat... but that person is not the person for whom it was written.
Personally, I find it quite refreshing that someone, man or woman, has acknowledged that sometimes a woman will want to actively fight to regain something so broken. And to do so without judging her as being weak, sick, wrong, etc.
I'd say the same if it was written by a woman or for men wanting to win back a cheating wife.