This is a question I struggle with myself on a regular basis. Can abusers really ever change or is it just theater to try to pull you back in so they can mistreat you again? Should you ever let a prior abuser back into your life if they seem to have changed for the good?
None of these are easy questions and there are certainly many contributing factors that should be considered as well. Perhaps abusers who once had drug or alcohol addictions and have now gotten clean for a significant period of time will have changed enough to give them a second chance.
What about those who lived for years with undiagnosed, untreated mental illness and finally get the help they need? How much of the abuse was who they truly were and how much was the influence of the untreated mental illness? This scenario is one I personally have experienced to some extent with my own family. How much responsibility should they hold for the abuse, especially any times they may have actually dipped into psychosis?
I know many abusers find religion at some point in their lives and claim to have been completely changed. I must admit I am suspicious of this claim. Perhaps religion truly does change the hearts of some, but much of my personal experience has taught me that if someone is a bad person before they find religion, they will likely be a bad person after they find it. Superficialities may change, but does their behavior/attitude/actions?
Unfortunately, I have no real answers to the question of whether abusers can ever change, but I hope that they can. I would warn everyone to be cautious in extending an olive branch to anyone who has deliberately hurt you again and again, but I do understand the desire to believe in the power of change.