Successful relationship with a sociopath?

It probably depends on your definition of success. From a reader:

Thank you for your site. Every other website about sociopathy I have read describes the sociopath as an evil unfeeling predatory monster out to steal your life, money, and children while raping your mother and pouring sugar in your gas tank.

My boyfriend is a sociopath. He told me that towards the beginning of our relationship. While that has resulted in problems in the relationship (understandably, mostly MY problems-he didn't see anything wrong), I have found that communication and understanding has made the relationship possible. We know that there are just some things about each other that we will never understand. He doesn't get how I can be so upset over something like a relative getting cancer ("he's smoked for years, WTF were you expecting?), and I don't get that he can't see that that response out of him doesn't help at all, and can't "feel my pain" as it were.

I know when to back off and let him have his temper tantrums when he gets frustrated or whatever it is that sets him off on a yelling spree.

I know that if I were to loan him a chunk of money, I would never see it again. Even if he said I would. So I don't.

I've learned to expect the unexpected from him.

I've learned when to ask him for something he doesn't like doing (putting on his "normal person" mask and hauling him off to visit my mother, for example), and when to just drop it and go see mom by myself because it will be more pleasant for everyone involved.

I've learned that when he says he loves me, he can't mean it in the same way that I love him; but that doesn't make whatever he is experiencing insincere or false.

Back to you, m.e. Reading more insights in to how sociopaths think has been extremely helpful in trying to understand what I should expect, what I should ask for, and what I need to accept is simply him- unchangeable, undeniable, just like his eye color or height.