A scorned husband is suing Sidwell Friends School for $10 million, saying the elite private school allowed its staff psychologist to carry on an affair with the married mother of a 5-year-old student he was counseling, causing trauma to the child. James Huntington was a middle school counselor who taught sex education to sixth-grade students in 2009-2010 — the same year that President Obama’s daughter Malia was a sixth-grader at Sidwell — when Tara Newmyer asked him to evaluate her daughter, a prekindergarten student.