Perhaps not surprisingly, the above referenced article suggests that there is a connection between martyrs and the conscience-less:
Martyrs are often attracted to difficult and abusive people. They have a compulsive need to change them, make these people good, and make them appreciate and respect them. They pick spouses who are brutal or intolerant, who lack a conscience, who deceive and manipulate them, and who resist the martyr’s efforts to reform them. It is interesting that they unconsciously choose to be around impossible people, and that their efforts to rehabilitate the latter are doomed to fail.
Do they really want to change us? Or do they just like the abuse? I'm inclined to think the latter. My thoughts are that it's generally understood that people don't change so if people are around me, it must be because they like what I'm dishing out.