The right counselor or therapist can do wonders, but the trick is finding the right one. Last year my daughter strayed from her marriage of 2 years, according to her (and I believe her) they did not "go all the way", her husband learned of the discretion from the other man. I am very close to my son-in-law and he confides in me often. The chose to save their marriage and went to counseling both together and separately and it has made their marriage stronger than ever. SIL continues to occassionally (understandably) have anger over the matter but through prayer and counseling he is dealing with it wonderfully. I had anger at my parents for abusing me as a child (father abused mother didn't protect) for over 30 years, a large part of my drinking problem. When I got sober I slowly realized that is was long past time to forgive and I spoke to them on the phone and decided to work towards reconcilliation, my mother died 5 months later before I got to be with her. My father and I are best friends now. The anger and resentment is hurting YOU, don't wait until it's too late.