"Dear Prudie,When I was 9 years old, my parents divorced and both remarried. I lived with my mother and stepfather. When I was 17, Mom and Stepdad had to move to another city, so I moved in with Dad and Stepmom. My father's new wife was a much younger and very attractive woman.
The atmosphere was more relaxed than in my previous home. So much so that my stepmom (she's about 15 years older) and I developed an attraction and started an affair. We were intimate about twice a month when my father was traveling for work. From Day One, we agreed that we would never tell my dad. I continued to see her during college and even after, when I came home for visits. 
My attraction waned because of distance, guilt, and because I started to see that she was a horrible person who was terrible to my father. I broke it off two years ago. 
Last month, Dad found out that she had cheated with another man (not me). They are in the middle of a vicious divorce. Last week, she called me and asked why I am so aloof. She told me that if I don't convince Dad to concede on a financial matter, she will spill the beans about our affair. 
I feel like karma is giving me what I deserve, but I am scared. What is better: try to reason with this woman, even though she is irrational? Do her bidding in order to save Dad greater pain? Tell Dad everything myself, knowing that things will never be the same between him, me, and the rest of my family? I just want to do the best thing for him at this point, and I feel powerless.—Karma's Bitch Boy
Dear Karma,As Simon and Garfunkel said so eloquently about a similar situation: "Koo koo kachoo, Mrs. Robinson."
Not only has this woman had an affair with her stepson and been multiply unfaithful to her husband, she is also an extortionist. The pain of extracting her from his life will be well worth it to your father. 
Now that she's threatened you, it will be hard to ever feel comfortable with your father knowing she's always fingering the pin on this grenade. 
None of your choices is good, but surely you want to be the first to let your father know you weren't spending all your free time your senior year of high school in woodworking class. 
I don't know what your father's mental state or temperament is, so it might be best to deliver this news in a corner booth in a restaurant. That way, he's sitting down and you'll have some privacy, but if he snaps and starts strangling you, maybe the busboy can intervene. 
Tell your father you have been living with a sickening, shameful secret that has been a blot on your life. Give as brief an account as possible and emphasize that you were a minor when she seduced you. (It would help if you were also a virgin.) 
As horrifying as this revelation will be for your father, surely his lawyer will do a little happy dance when he or she hears not only this news, but that stepmom has been offering to exchange her silence for money. 
As for your relationship with your father, you're right, it will never be the same. But at least now it won't be based on deception.—Prudie
-- Dear Prudence, handling a situation Ann Althouse calls "lurid" - but TMR finds beautiful - on Slate.com.
