I too find myself in almost the same situation as you and it breaks my heart to know that my husband of 30 years has been bedding someone whom I had thought was a "friend"!
I have always believed that my husband and I were soul-mates, that we are supposed to be together. Both he and his whore (sorry for the foul language!) are aware that I know of their relationship. I have told my husband that I'm not "okay" with him doing this and I believe that he has not only betrayed me with his lies but he has also betrayed our children by lying to them about "their" relationship.
Both my husband and I are survivors of long term child abuse/neglect; his was physical abuse at the hands of his father mine was sexual abuse starting with my step-father when I was 6 and lasted for 12 years. It took me many years of individual therapy, regression therapy, Chakra Meditation, White Light Meditation among many other things to get me to the place that I am now. Finally at peace, knowing that I am strong and a survivor! My husband has finally decided to start therapy for his issues, and it is for that reason that I have chosen to stay even though I know he is unfaithful and currently has no intention of cutting off the contact with the other woman.
I have consulted my Tarot Cards many times since "confirming" (I had suspicions, but not the cold hard proof) and each time my card tell me that I need to be strong, steady, show patience, and stay positive. I believe that my husband is going through a mid life crisis and this along with his past trauma has manifested into this mess that we now find ourselves in. My hope/wish is that my husband will see this other woman for the devious, manipulative, treacherous, deceitful person that she is. Once that veil is lifted from her face and her true colors are shown I believe my husband will be able to travel farther down his path of recovery.
I know that she is all of these things because she has IM'd me on facebook with some of the most foulest comments! I know that they are already starting to fight and argue because my husband won't "rub" their affair in my face and let her come to OUR house. I know that she is still lying to her HUSBAND about sleeping with my husband. And I know that she has made "threats" to my husband about telling people at work about my past abuse to "embarrass" me so that I will quit my job!
So, I'm looking to develop a spell or find one that has already been used to "assist" in lifting that veil from her. But, before I try to fully expose her I will be doing a complete cleansing and purification of our house (yes, there were some very heated arguments before I was finally able to come to this point!) and I am in the process of making protection talismans for every member of my family.
I wish you the best of luck with your situation and I hope that everything works out for the best for you!
Please take care of yourself! Take no action if you have just found out about this affair... You need time to grieve, cry, scream, go for long walks if you need to. But right now you need to think with a CLEAR HEAD AND HEART before you take any action!