Mary Kay Letourneau

Formerly an elementary school teacher in Washington state, in 1996 she started an amorous and sexual relationship with one of her students, Vili Fualaau, at the time aged 12. She was turned in to the police by a relative of her husband at the time. She bore a son of him before her trial was concluded. She pled guilty to two counts of second-degree child rape and was sentenced to six months, three suspended.

While on parole on condition she have no contact with him, she got impregnated by him, was caught, and was sent to prison, where she gave birth, for seven years. After her release, once he was 18 (not 21, as Wikipedia says) they asked the court to lift the order of protection, and it was lifted. They married in 2005 and are apparently happily married still. She is registered as a Level 2 sex offender.

For details and references see the Wikipedia article on her. What the article does not say is that the boy's mother supported the relationship, saying that in their culture (they were from somewhere in the South Pacific) it was appropriate. The boy's father is not in the picture.