Exactly, if it's not rape it's ok in my opinion. Of course there's got to be some sort of restriction to protect the younger children, but the fact that you have to be 18 to chose who you want to have sex with is a ridiculous law. However teachers shouldn't have relations (sexual or not) with their students, as it's inappropriate ( grading, marking tests and such ).
it depends really, when I was in high school (more than a decade ago I guess) I remember my english teacher was in a relationship with one of the student and they were engaged once the year was over he married her, he is a professional and he did his job properly, and also their relationship was "clean", they only meet in public places or with the family I'm almost sure they married as virgins both of them.
yes exactly, the teacher-student relationship is a complex one, since usually we are talking about underaged or immature students and old teacher, also the nature of the relation/influence the relationship have makes things more complicated, but again in this case it's silly that one guy should go to prison if they were having consented sex, him being fired from the school is a punishment for it self since he did something morally wrong
But if it's not a rape then... 
