Another post on here brought back memories for me of having sex with my dad. It began after he found out I'd been seen kissing a boy from school, which made him feel jealous. He pursuaded me to give him oral and it just escalated from there. It stopped when I went on to college, but I found out that he had sex with my sister too. She said she enjoyed it. I did too, so no one ever said anything and nothing was ever done. What you call a victimless crime, I guess