Write them a letter, pack up all your belongings and find somewhere else to stay. Do not tell them where you are going. This way you will be safe and they cannot hurt you but you are still able to have the closure you seem to need. Let them know you are more than willing to talk about things to have more closure but that it must be done in therapy of some sort. You can find a therapist in your local yellow pages, possibly couples therapy or individual. If you do not have the means to pay for this service you can contact your local government that can refer you to somebody that will work with you on a sliding scale (based on how much you make). Good luck.