I read "Not 'Just Friends': Rebuilding Trust and Recovering Your Sanity After Infidelity" by Shirley Glass in the first few weeks/months following news of my husband's affair and found it to be articulately and logically presented, giving me greater understanding.
After a few months had passed and my husband and I reached a point where we both seemed commited to working on the relationship, I chose to delve deeper into the "how" of marriage repair with this book.
It has been very helpful and I have definitely benefited from reading it during the later stages of the healing process rather than during the confusion of the first few months.
As with most, the book has mainly been written for couples who hope to repair their marriage although the authors do not appear biased; there are example stories of people who choose to part as a result of their differences.
The book is full of practical suggestions for re-establishing lost communication, tackling the differences and coping with the emotional turmoil. It's not at all heavy going yet it covers most concerns in depth. I found advice on tackling sexual difficulties post affair especially helpful.
I would thoroughly recommend this if you have reached a point where both parties are willing to put in the effort to work towards a shared future.