If you have reached the point where you're certain that person has no conscience, or is in it to win rather than to love you, then the very best thing you can do is to get away. That's a very hard lesson to learn, and, furthermore, it's not always possible.

Sociopaths are not inhibited by the notion that it's wrong to be addicted, or wrong to buy illegal drugs. Also, drinking or taking drugs can be a lot of fun, and even if it's not, it can dull that painful boredom for a while. So can certain other things, like taking risks, and particularly if you take a risk-averse person and you can manipulate him or her into taking risks, that's really fun.

Controlling others—winning—is more compelling than anything (or anyone) else.

The bottom line for most people who are normal is their need for other people. Even the greedy ones have this need - as long as they're not sociopathic. They may be very misguided and unhappy and do bad things and so forth, but in general if you look down deep, you find that these people are mainly concerned with other people and what other people think of them.

Even famous people - are most concerned of all with what people who are close to them think. And the sociopath is generally not concerned with that at all.

The perfect victim, from the sociopath's point of view, is the person who is smart enough and capable enough to do him some good in the world and who is also fun to manipulate. How much fun is it to manipulate someone who is stupid and incompetent?

If you have reached the point where you're certain that person has no conscience, or is in it to win rather than to love you, then the very best thing you can do is to get away. That's a very hard lesson to learn, and, furthermore, it's not always possible.