it is also important to understand the difference between "sociopathy" and "psychopathy". sociopathy is a condition that is created by extreme abuse in early childhood, and a failure to bond with caregivers (in general terms). psychopathy is the absence or impairment of glands in the brain which allow certain behaviors, like impulse control.

it sounds to me like you are describing psychopathy, for which there is no cure. the only treatment is behavior modification, and since people with this disorder tend to be highly intelligent and manipulative, behavior modification is very hard to implement. a person with that condition might be able to live by RULES most of the time, unless the environment offers triggering stimuli.

essentially, it is not safe to be casual about any relationship with persons who have either type of dysfunction. wish you the best~~