"We all see the world through tinted eyes" comes to my mind. Much as I am certain we all try, it can be very very difficult to truly put ourselves in another person's shoes and see their "tinted" version of the world. Even harder is removing our tint to see the world the way it really is.
I believe everyone has a tendency to victimize themselves, because everyone is trying their hardest to be a good, decent person and can only see, from their own perspective, the people, events, things etc that get in their way and make their journey difficult. Whether or not we really are victims, we all sometimes feel like the whole world is against us, the people we love just don't understand, and those we should be able to trust are out to get us.
Because of these individual biases and our imperfect perceptions, another difficulty can be removing our walls, guards, and barriers that we put in place to protect ourselves from hurts (unintended or purposeful) of similarly broken people in the world just trying to make the best of their lives. We get hurt, and we hurt those around us, and we all just have to keep picking ourselves back up and keep trying to push forward.
Relationships can be especially difficult, because they require extending more trust, exposing ourselves to more possible hurts, and making ourselves more vulnerable than any other situation or circumstance we can place ourselves in. I am fairly certain that even those people who cause us terrible pains are "good people" in their hearts, and I believe that no one is entirely innocent of causing harm in the event of a broken relationship.
An abuser is someone with a strong will, used to getting their way, difficulty feeling empathy or recognizing signs/body-language indicating discomfort or unhappiness in another, and glasses tinted to view anything not going their way as an assault on their person. They find themselves paired off with those who are weak willed used to giving in, extremely sensitive to the signs/body-language of others, and glasses tinted to view themselves as failures whenever things don't go as planned. Why do these pair ups happen over and over again? Because these two personalities feed off the weaknesses of the other, strengthening the abuser/abused relationship instead of strengthening the individuals to help them overcome their weaknesses.
I believe that neither individual in relationships like this are truly "bad". Certainly, when the abuser chooses to consciously harm their partner, they are in the wrong, but they cannot conquer these demon on their own anymore than the abused can. Both need help. Both need healing. Both need to recognize the flaws and weaknesses in their personality so that they can be worked on and overcome, so that the individual can become healthy and seek out a healthy relationship.
The same analogy comes up with supporter/sufferer relationships. Those who are suffering seek a relationship with a supporter. And those who wish to be supportive seek a relationship with a sufferer. The difference here, from the abuser/abused relationship, is that a supporter/sufferer relationship has a greater potential for success IF the supporter can assist in truly strengthening the sufferer. Unfortunately, there is also great potential for a supporter/sufferer relationship to turn into an abuser/abused relationship, with the sufferer taking on the role of the abuser and the supporter taking on the role of the abused OR vice versa, depending on the innate personality traits and weaknesses of each.
I believe the only solution, the only way to cease perpetuating the cycles, is for all of us to cease seeing ourselves as victims. No matter what role you have been placed in in past relationships, no matter what role you currently cast yourself in, you are only a victim if you choose to be a victim. You are only a victim, if you see yourself as victimized. We are all equally broken, and as long as we keep relying on a relationship to fix us, we will remain broken. We should seek relationships with those who help lift and strengthen us, with those who encourage healthy choices, those who stand up for themselves without rudely stepping on the toes of those around them or cutting them down. And we should each strive to be just such a person to those with whom we have a relationship.