I'm a 20-year old college student who is not even close to getting married. It's not that I'm opposed to it or that I want to put it off until a later age either. The main reason is that the relationships I see around me are just not capable of the long term like marriage should be. Basically, as this book points out, relationships are gotten into these days for the wrong reasons (for lust, convenience, etc., etc) and they cannot possibly succeed in finding the kind of connection necessary for the long-term.
While this book is good, I think it is a better perspective to gain before you get married. In a lot of ways, this book encourages people to rethink their current relationships in the service of finding a lasting love. And that is all good and well. But the advice is much better received for younger people who haven't gotten married yet, for those who are still trying to figure out what they want in a relationship, and for htose who haven't already made a commitment.
If you have read any CS Lewis and in particular, the Four LovesThe Four Loves, this will ring a bell. I am also reminded on a short book by ER Morse called Love is JusticeLove Is Justice: An Exploration into Mankind's Fundamental Nature. The notion with all of these is that only with a confident look at God can you look at others--you must first be in love with God before you can truly love another person.