Seeker,
IMHO if we are still having dreams and upsetting thoughts about a person, then they still have some form of power over us. It is like they have left us with a bad smell that we can't get rid of. Of course, if this person was a parent or guardian, then so much the harder.
Real freedom comes when we can think of that person as a problem for anyone they have hurt, and as a problem for themselves. We have finally detached from them when we can visualise them for what they are, or have been, but not in connection with us any longer.
One life coach said that anger from being hurt and duped can take a very long time to pass, and we have to let it take that time, commensurate with the original pain. We can't avoid it or dump it on others.
Once we have been through the process, then we are free to move on, and hopefully to avoid the situation happening again. We will recognise a new situation by the feeling it gives us, and avoid getting burned again.
Fire burns us, but we don't need to feel angry that fire exists, we just have to step aside from it. The key, in my view, is to see the sociopathic individual for what they are, and step aside from them in future. It's a tough lesson, but there are plenty of people out there still learning it, and who will have to learn it in the future.
Peaceful thoughts, M