The sad thing is that on either side of the fence, the other party, in this case, your W, usually is mistrusting of "advice" that is thrown over the "fence" to them.
While the book may have some GREAT advice (not personally familiar with it) that could help her and your marriage, the fact that YOU suggested it to her taints it.
Also, one thing I will throw out there is that many times us H's get caught up in "fixer" mode and react to something that our W's are venting as something that they want us to fix when the truth is that they just want us to listen, validate and then move on. Mars/Venus gets into this a lot but I feel that maybe in this case, your W was not looking for you, ESPECIALLY YOU, to fix this problem she has with her desire. She was just expressing her feelings about it, something I bet took a little strength to do. When you tried to "fix" her by offering her the book (oh, BTW, you already having ordered it may have made her feel bad too), you put her off and she recoiled.
This is JUST A POSSIBLE scenario but one that seems plausible to me.
So, I agree, let it drop. She knows you have the book. Unfortunately they just need to come by this stuff on their own and WANT to get the info. When she wants to bad enough, she'll seek it out, and maybe seek YOU out for the book.
