One of the best things I did for myself and my Marriage was to purchase a book called Torn Asunder by Dave Carder.
It was recommended to me by a women who’s marriage also suffered an affair and survived. I will warn you, it dose have Christian themes, but the information is priceless.
This book is for any stage of the affair and I recommend it weather you decide to try and save your marriage or not. I hope this book helps you as much as it has helped me.