http://www.dearpeggy.com/free-pdfs/help-for-therapists.pdf - this will allow you to download a PDF of Peggy Vaughn's book
Help for Therapist and their Clients.
She presents results of her survey of volunteers who had experienced infidelity, the survey itself, and loads of comments from the volunteers.
PV died in November, 2012, and her will directed her publications to be available for free as long as possible, which was very generous, and there's a lot of stuff there.
