4. Thomas Jefferson
Thomas Jefferson was sexually involved with his slave and maid Sally Hemmings, a woman 30 years his junior working as a servant in his house. It was strongly rumored that he fathered six of her children, which was later proved by DNA results in 1998.
Although many people believe that they were involved in a relationship, recent studies believe that their affair could have been non-consensual since Hemmings was a slave woman.