Being a liar or sexually promiscuous does not make you a sociopath, though they may be common traits shared by sociopaths. The typical definition for a sociopath implies a lack of guilt or remorse. That being said, sociopaths are incredibly good at concealing this deficiency. Even the best would have trouble identifying them. It is possible that he is indeed a sociopath, and it is possible he is not. Without more information it is really impossible to tell. If he is a sociopath, he will drop you like a hat made of lead if he sees fit.
Also, the others who have replied have it right in that having a personality disorder does not make you more compatible with others who also have disorders. Sociopaths in particular, seeing as how they are incapable of forming any real emotional connections should be avoided especially concerning intimacy.