I'm sorry that you've had such terrible experiences. The thing about sociopaths and how/why they enter our lives all boils down to our personal choices, flawed "beliefs," and (in most cases) core-issues that have not been resolved.
Flawed Beliefs:
* everyone deserves the benefit of the doubt
* everyone deserves a second chance
* I have the ability to make other people happy
* I am responsible for the happiness and well-being of others
"Benefit of the doubt" feeds cognitive dissonance which is when one person's actions/behaviors do not FIT into our own system of beliefs, and we attempt to force ourselves to rationalize those actions/behaviors so that they DO fit into our system of beliefs. Example: I would not deliberately set someone up to take their money from them by coercion or outright forgery, so anyone that I care about or love would maintain the same values. "Second chances" only perpetuates the cog/diss and exploitation of our core values. I have control over one thing, ONLY: myself and my choices. I am not responsible for anyone else's happiness or well-being. Understanding control and responsibility allows for me to construct and maintain strict boundaries, across the boards with ALL people, and I am not obligated to tolerate anything that is harmful to me.
Core-Issues:
* shame-core as a result of emotional/physical abuse
* guilt-core as a result of emotional/physical abuse and trauma
Shame-core as the result of being raised in a dysfunctional environment, and this requires intensive work with a professional therapist that understands this concept, along with guilt-core. I'm addressing both of these core-issues with some serious focus, and I no longer require the approval, acceptance, or validation of anyone outside of my Self. Therefore, if someone attempts to trample my boundaries, they're OUT without anger, resentment, or ill-will. They're just out, that's all.
I don't know what your personal experiences have been, and if you believe that you are attracting or choosing sociopaths, it might be a very wise option to consider counseling therapy with someone to address what could be seriously flawed beliefs and core-issues.
Best wishes to you