Addiction to unproductive, non-supportive, and hostile relationships is easy to get used to. This is precisely because you did not get here overnight. You gradually slipped into allowing it become this way.
We all have a desire to be loved, wanted and appreciated. Sometimes though, we just get confused about what constitutes a good relationship as opposed to one in which we seem to have a role that is perhaps less clear cut than we see it as being.
Being stuck in old patterns of relating to people might mean you are always the giver and yet you don't seem to be appreciated or nurtured in return. Perhaps you are not even acknowledged for the good person you are. Could it be that you are being taken advantage of?
On the other hand, maybe it could be the case that you are the one in some of your relationships with others where you are taking someone for granted, and their own contribution to the relationship is going un-noticed or un-acknowledged by yourself.
A simple stock check or tally of the important relationships for you will allow you to see what is working and what is simply painful or wrong.
Be clear with yourself and with the other person that what has been tolerated until now can no longer be allowed to go on, that you are unable to stay engaged in such a relationship and that you will have to remove yourself from it. If this is a relationship that is casual, temporary or one that is occasioned through work or the proximity you have to the person concerned, then it is easier to deal with perhaps, than where the relationship is a very significant one and closer to home.
But the truth remains, you cannot do any good to yourself or for yourself if you remain in the place that is harmful to you. This is not an easy decision to make, and you may want to seek professional counsel or the guidance of a friend who already knows you well in order that you can have an opportunity to talk through your thinking and through the implications of any of the decisions you might seek to make.
In any of these discussions maintain your focus on the real goal of letting go of the relationships that are not in your own higher interest.