I was friends with 2 other women for 20 years.
One I knew had real paranoia problems caused by her family but she kept trying to control me. I just forgave her and stayed loyal to her despite what she threw at me. Then one day she accused me of deliberately hurting her grown up daughter. I was so shocked that I e-mailed her back and told her I did nothing and perhaps we should meet somewhere public to talk it over face to face. She refused. I haven't heard from her for years and it was like a divorce for me. I loved her unconditionally but she wanted to control, to this day I think she is waiting for me to come on bended knee to apologise and that's never going to happen.
I have spent my life being bullied and abused and it is only now that I am starting to see how toxic these relationships can be.
The other women took, took, took and I gave, gave, gave. She suffered from some child abuse and I felt she needed a friend to support her. I would always listen to her problems and try to help. Sometimes she would ring me, crying, 3 times a day. I would always listen and try to help if she needed me to and I was there for her. Whenever I had a problem she would change from friend to counsellor (She had done a counselling course) and start to try to solve my problems instead of just listening and sharing. This lady never married and did not have children.
My husband saw early on that this lady was bleeding me dry but I never saw it. My lads saw it too and they all tried to warn me. I should have set better boundaries. Sometimes she would turn up at the house in the morning and still be there late in the evening. I would put my fire on to keep her warm, feed her and do her course work for her many college courses. In the end it was obvious that she was uncomfortable around my Son and we had a big argument which started with her screaming at me in my own kitchen and not allowing me to speak. She wanted me to her self but she didn't want my H and kids around, not even in their own home - big mistake!
The next day I range her to try to talk about it but she cut me off. I was devastated and grieved long and hard - I still do. But, with my husband and children's help and that of my Therapist I have learned some valuable lessons.
1.I have learned to evaluate these friendships. As has been said before, what did I get out of them? Well, in honesty, very little. So why did I stick with them? Because I was lonely and better a bad friend than non at all right? Wrong! It is better to have an enemy who is obviously an enemy than a friend who pretends at being a friend.
2. I am learning to recognise poor friendships before I commit to them. Someone else offered me friendship recently but I turned it down. She wants my problems so she can 'help' me with them and feel good about it. She doesn't want 'me' as a person so she is kept at harms length. She doesn't like it but that is her problem not mine.
3. I am learning to set realistic boundaries. My T tells me that friendships are like concentric circles. In the outer circle are lots of acquaintances, they are there but never get too close. Further in there are those who we see more often and are closer but the inner circle is reserved for those we truly love and trust and who love and trust us. It is sacred and few get in it.
4. I am stepping out of the 'triangle of abuse.' This is the drama triangle my T taught me:

Those of us who have been the victim send out signals to the persecutor and we are attracted to them. The persecutor does not show their true colours at first but eventually does. By then the victim is 'stuck' in a rut and cant seem to get out.
The rescuer then steps in to aid the victim (I prefer survivor). Often, those of us that were victims turn to rescuing others which can be a good thing. Often, the rescuer ends up persecuting the persecutor in order to save the victim and becomes the thing that he/she hates (a persecutor) and the persecutor becomes the victim.
So you can see how it becomes a vicious circle. Those of us who have been victims do tend to attract the toxic and, because our lives have been hard and lonely we stay with the abuse. But we need to learn how to 'step out of the triangle.' To be neither victim or rescuer and definitely not the persecutor.
My T also told me that as I change I will attract new friends who are very different from the people I use to know.
Anna and others, I truly hope this helps and I sympathise. Breaking off friendships is truly like a divorce and can take time to heal but we are most definitely better off without them.
((((HUGS TO ALL))))