A Proscriptive Relationship by XxSkater2Girl16xX (and its sequel, see XxSkater2Girl16xX's profile)
Description:
Holly's new, young teacher has a dark past, and a dangerous future. She soon finds herself charmed by his ways, and gets thrown into the chaos. Who knew having an ex-gangster for a teacher could be so troublesome? As Holly and Mr. Heywood grow closer, more questions about his past come upon Holly, as does danger. What is Mr. Heywood keeping from Holly? And why is it so bad? But most importantly, if she falls for him, could their relationship survive? After all... it would be a proscriptive relationship.
Completed, worth reading!