Something Borrowed By Emily Giffin

From the Back Cover:

Rachel White is the consummate good girl. A hard-working attorney at a large Manhattan law firm and a diligent maid of honor to her charmed best friend Darcy, Rachel has always played by all the rules. Since grade school, she has watched Darcy shine, quietly accepting the sidekick role in their lopsided friendship. But that suddenly changes the night of her thirtieth birthday when Rachel finally confesses her feelings to Darcy's fiance, and is both horrified and thrilled to discover that he feels the same way. As the wedding date draws near, events spiral out of control, and Rachel knows she must make a choice between her heart and conscience. In so doing, she discovers that the lines between right and wrong can be blurry, endings aren't always neat, and sometimes you have to risk everything to be true to yourself.

***

So I'd written about the movie here, and once I came to know it was actually based on a book by the same name, I had to get it cause I really liked the movie, and the book was better than the movie (which is almost always the case!).
 
There are a few differences between the movie and the book, the major ones being the role played by Ethan, which is pretty small in the book, as compared to the movie, and the part just before the ending, which I'm not giving away.

The constant struggle in Rachel's mind between happiness at being with the man she loves, and guilt at cheating on her best friend, however malicious she is, is the crux of the book.
What I didn't understand was how someone supposedly as smart as Rachel couldn't figure out that her best friend has been sabotaging here from the very start of their friendship, and also  how could she continue seeing Dex, when she can see that he's not doing anything to end the relationship with Darcy!
I guess where your near ones are concerned, one can be quite blind to their faults.
 

***

Some memorable excerpts from the book, all a part of Rachel's internal monologue:

I am a good friend. A good person. This isn't who I am. I must stop. I won't know myself if I don't stop.
Yet I don't move away.

I will tell him that it has to stop. This time I really mean it.  

How can I end something that I have never experienced before? Something I have been waiting for my whole life? Nobody before Dex could make me feel this way, and what if I never find it again? What if this is it?

I used to wonder how they found people who had committed such acts of despicable disloyalty. Now I was joining the low-life ranks.

Maybe it is meant to be.

"What are we doing?"
There it is. The Question.
Every time I answer it differently:
We are following our hearts.
We are taking a chance.
We are crazy.
We are self-destructive.
We are lustful.
We are confused.
We are rebelling.
He is afraid of marriage.
I am afraid of being alone.
We are falling in love.
We are already in love.
And the most common: we have no idea.
This is the one I offer up. "I don't know."

She is subdued. Something is wrong. Maybe there is trouble brewing at home, a visible crack emerging in their relationship. Maybe Dex said something to her. I feel a surge of hope, which is followed by a larger dose of guilt. How can I so easily root for my friend's unhappiness?

And the best one:

Life's not black-and-white. Sometimes the end justifies the means.