Office relationship drama and legalities?

I recently started working in a dental office and have a bad situation in my hands. When I interviewed, it seemed like a great job and I was really excited to start. On my first day it was a totally different story. The office manager and the Doctor are constantly fighting and acting extremely unprofessional around the patients and taking out their anger on all employees, myself included. I found on on the second day that the office manager and the Dr. are having an affair (the Dr is married) and are fairly open about it, although so far I have no concrete proof. At first I thought I might have been over-reacting, but looking through previous records, they have fired all employees within 6 months of their start date for 3 years. I found out my neighbor used to work for them and was fired without a reason. I want to protect myself, and I would love to quit, but I don't have another job lined up and its going to be very difficult to find one after working at this office for a mere week. I want to know if anyone has any advice or knows what the legalities are for the Dr. and the office manager having an affair. (also, creepy... the manager is 24 and the Dr. is in his 60s) Help!