While this is not technically a theological work, it certainly would make an excellent book for relationship counseling and even premarital advising. The Five Love Languages by Gary Chapman has quite a bit of very solid advice in it.
Which is not to say it's a flawless book. There are some gender stereotypes in it that make me wince- all women like shoes, men can't multitask, etc. And the voice of the book isn't really my cup of tea, though you may like it. It is very clearly a book that was written for people who like the books you find in Christian bookstores. And I realize this blog is young yet, so you may not realize this, but to be strictly honest I've investigated a lot of books in Christian bookstores (professional hazard, you might say) and it's not a voice I favor. A little too glib and shiny, ignoring the darker side of things, pretending that we live in a perfect world. Not really the voice I'd go for in a book focused on relationship counseling.
So, this book isn't intended to help someone recognize and escape a bad situation, but it does have some very practical advice about relating to another person. The general concept of the book (as you may have guessed from the title) is that there are (at least) five different "languages" that we use to express and receive love. Someone who prefers to receive love from their partner with words may not recognize that their partner values acts of service more. And so one partner is constantly saying I love you, and the other is constantly doing little chores around the house, and both are flabbergasted that neither of them seems really fulfilled.
The five love languages are (paraphrased) physical affection, words, gifts, acts of service, and quality time. And lest we jump to conclusions, there are many ways that all of those can be expressed- gifts don't have to be expensive, and some people value a hug over a kiss. A person may have two preferred love languages, and certainly may really dislike one or more of them as well. (I know a lot of people who don't really like receiving gifts, for example, for a variety of reasons.) So it's a bit more complicated than you'd think at first, but Dr. Chapman does a good job of laying it all out. Also, it's the kind of book where, if one person in a relationship is more of a reader than the other, the basic concepts can be easily relayed.
So it would be a lot of use to someone who's just feeling a bit disconnected or unfulfilled, but isn't necessarily the first book to reach for in extremely miserable situations, by any means. Also, the concepts are easily translated into relationships that aren't romantic- Dr. Chapman apparently has a whole series worked out by now. I haven't read the others- I may some day, but my too-read list is long enough it won't be for quite awhile- so I can't review them. But if you like this style of advice book, investigating them might be right up your alley.