Your ex is the first one you can think of. You think you will feel better if you can somehow make them miserable. A lot of divorced people don't want to take their lives in their own hands. Therefore some think if they are miserable enough and a failure as a functioning single person, it will make them more lovable and if they act helpless enough someone will come along and take over for them. I'll just stay helpless-someone will rescue me.
People are afraid of change.
I may be unsafe changing. You quit it finally when you find it is not working. Initially after divorce we are haunted by memories of what was left behind and terrified by tomorrow. You need every bit of your emotional energy to make today a bright day. A happy successful life is a series of happy days.