I am sorry to hear what you are going through. An employer is liable for the tortious conduct of an employee only if that conduct was committed in furtherance of the business of the employer. Without further details or information, it is difficult to conceive how the spreading of negative rumors about one customer to other customers can be considered to have been done in furtherance of the business of the tavern. Thus, without more than what you have described, it is not likely that the tavern-employer could be held legally liable for the employee who is talking about you. Defamation is the making of false statements of fact about one person to third party(ies) which caused injury or harm to the person who is the subject of the false statements. False statements about a person's sexual promiscuity, etc., can certainly cause damage to one's reputation, etc. so you arguably might have a claim against this person (be aware, "truth" is a complete defense to a claim of defamation, even if it causes embarrassment, etc.,) and may want to consult a personal injury attorney in your area for a privated discussion - you don't want to post intimate or personal information on a public website such as this. One important consideration is that even if you sue and won, does the employee have sufficient personal assets to collect against. If not, you could wind up spending a lot of money and time and still not collect anything. Good luck.
A roundup of the best tips and legal advice.