This book sounded like such a good idea. It goes with a movie (Christian-based starring Kirk Cameron) called "Fireproof". The movie was quite moving for a woman like me - it was given to me to watch by a neighbor who swore by it.
Just like the movie, the book is based on giving up YOUR OWN expectations of how your SO should treat you, and makes you focus instead on how YOU should treat THEM - and in so doing, it will make them WANT to treat YOU better. It indeed is a powerful reminder to be the best YOU that you can be.
If you are the BS, a lot of times there's nothing you are going to do to "woo" your WS into giving up their affair partners. By the time there's a third party involved in your marriage, the measures outlined in this book would most likely just seem like cheap tricks to get your WS to pick you over the AP.
I didn't know my WH was cheating at the time my neighbor gave me the book, but as I flipped through it and after having watched the movie, I realized there was NO WAY I could treat my husband (didn't know he was cheating at the time) the way the book outlined. It gives you a 40 day plan (just like Jesus 40 days in the wilderness fasting and "battling" the devil, I guess...) - a different thing to do every day to both treat your spouse better/with higher respect or esteem, and to get YOU to see things in yourself that you could change to affect positive changes in your marriage. My marriage was so messed up at that point that I knew I couldn't GIVE my all to that book - it would have meant showing my husband respect, which I very much didn't feel at that time.
Fast forward less than a year: I find out the neighbor who gave that book to me is one of the women having an affair with my husband...
People never cease to amaze me in their denial - myself included...
Good for you for trying it out - it's worth looking at, but don't beat yourself up if it's not something you can complete.