John and Stasi Eldredge are very open and honest about the fact that all marriages, theirs included, are hard. This is because marriage is intended to be something that God uses to change us and our world - and because of that, it's something that Satan loves to attack. In Love & War, the Eldredges talk about what marriage is meant to be, how we often mess it up, and how God can redeem those mess ups to put us (and our marriages) in a better place. They also go over some of the more typical themes you see in marriage books - though even these have a different feel, perhaps because it's clear that the authors have struggled through them and come out on the other side victorious.
This is an uplifting, challenging, and thought provoking book and something that will benefit you, no matter where your marriage currently is.