It is not "harassment," but it may be defamation: defamation is the making to third parties (so to anyone but the actual target of the gossip) of untrue factual statements which damage a person's reputation. A false accusation of an intraoffice affair and inappropriate onsite sexual conduct could certainly constitute defamation. From what you write, it may be worthwhile to consult with an attorney (probably a personal injury attorney) to see if you have a claim and what it might be worth. Good luck.