When your wife wants to get books that she believes will strengthen the marriage, be supportive. Trust me, it will work out for your advantage if you are engaged in this process.
My wife wanted to get a bunch of couple devotionals after we got married. I was resistant to this because a lot of them were written for people who were adjusting to getting to have sex. My wife and I did not feel like we needed those types of devotionals so it knocked out a lot of the newly wed section.
I was resistant to the idea the whole time because we had devotionals at home already, and because I resented looking in the newly wed section and being among the books that spend so much time communicating that its ok to have sex. (Something that does not bother me.)
After a lot of search we found a devotional that we thought we could stomach. And finding it gave my wife some peace and comfort about how we were starting our marriage. Her comfort led to better things for me.