I'm a stayer. Here's my story of how I escaped from Oz, and how I stay with the BP in my life (for now anyway). I can do this and still consider myself a resident of Kansas. I don't recommend this for everyone, but if you want to give it a try or you can't leave it may be helpful.
The first step was just a lucky accident. I was browsing in a bookstore, looking for a specific book on relationship problems. I saw the title, "Stop Walking on Eggshells." That was exactly how I described my life. I grabbed the book, looked at a couple of pages, and decided that I needed to read it.
The next step was information gathering. I read the book at a lightning pace. It seemed like every page had a new insight for me. I spent most of my time for awhile just absorbing what I had learned. I reflected on past events, and I could see now that so much that was wrong in my marriage was the result of my wife's BPD. This step took a long time for me. I did a sort of retroactive journal. In it I wrote about memories and related them to what I had learned about BPD. I was depressed some at this time. I don't call the depression a step. I know it's a normal phase, but it didn't do anything to get me to a new place.
I read a lot of books: "Love and Loathing," "Emotional Blackmail," "I Hate You Don't Leave Me," and "Too Good to Leave Too Bad to Stay." I joined an online support group. (This one didn't exist then.) I found hope. I got over being depressed. I realized that the information I had couldn't help me unless I took some action. I realized I had to decide whether to stay or leave.
My first decision was to leave. It really seemed like there was no alternative. It seemed like the only way to stop the abuse I was living with. I talked to my kids. I made a trip to visit my brother and other family. They were all supportive. My "kids" were all adults at this time. I didn't have to worry about custody or where they would go. I did want their input.
I made my escape plan. I talked to several lawyers about divorce. I selected one. I set money aside for his retainer. I began looking for a place to live. At that time I was working away from home during the week and coming home on weekends. It would be easy to just stop coming home. I could eventually get an apartment near home.
The next step really wasn't planned either. It was meant to be a temporary thing - like the doughnut tire on your car that you use for a spare until you can get the full sized one fixed. I realized it would be a problem doing a divorce while I was out of the state so much. I was also having powerful, troubling dreams that seemed to be telling me I wasn't ready to make this move then. I decided to put off making a decision. It was reasonable to wait until I could change jobs and be able to stay be in my home state to do the divorce. I also decided to try boundaries as a way to make my life better until I could get back home.
I decided to try a boundary about her rages. That was the keystone of all her control. She could devastate me by raging, and she could get away with any other abusive thing by raging or threatening to rage if I resisted. In setting the boundary I broke all the rules about communicating with a BP. When she was in the middle of telling me how terrible I was I just decided I couldn't take it. I blurted out that she had to stop or I would leave. I added that any time she did it again I would leave. She tested the boundary later and I left the house for a few hours. When I got home she acted as if nothing had happened.
I had said nothing about abusive phone calls, but when she started on me over the phone one day I hung up on her. She called back a few minutes later. She was calm and said, "You hung up on me." I said "Yes, I did." That was that. The boundary worked beyond any expectations I had. She quit raging. Even better, I found that I could tell her "no" about other things without her escalating to a rage. My life got better.
Interestingly, I believe she is happier now. They say that children feel safer and more secure when they have limits. This seems to be true for my wife. It may work for you.