You write about things that are deep and painful. Do you emotionally relive the painful feelings and experiences? Does the process of writing your novels bring pain or relieve it? 
I write about things that make us human. There is a great Zen saying that goes: when you meet someone, look them closely in the eyes, for inside those eyes a great battle is waging. Really all of us human beings are essentially in the same place. We are on a battlefield. Each battlefield may be different, but in the end, we're all facing some very human things: aging, loss, sickness, and death.
Someone asked me once if I have a writing muse. I answered that I go to where it hurts inside me. Or I go to where I feel most afraid. Where we find resistance inside us is where our muse lives.
While I am writing I feel the pain, or I purposely go to where the pain is and conjure it up. The trick for me is that I'm writing in first person. I have invented an "I." And this invented "I" as soon as I write it down is not "I" the writer but "I" the narrator. The narrator almost immediately begins to lie. I think it's practically impossible to make the invented "I" not lie. The invented "I" is fictive and cannot be the same as the "I" who is writing. The invention is by its very nature different than the inventor. So as soon as this new "I" starts to speak, it has an existence of its own. I don't think there is a way around it. After a couple of pages, the "I" that I have created may look like me, and have the same hang-ups as me, and may have the same sense of humor, but there's something different about this new "I." And the difference is: this new "I" is not me, but an invention of me.
In my opinion, this invented "I" is quite different from a third-person invented "he" or "she." Speaking as the "I" keeps the narrator actively in the story. The story is happening to the "I." With the third-person narrator, the story is happening to this or that person over there ("him" and "her"). Third person places the narrator, as an awareness, perhaps omniscient or "close-in," but always outside the events that are happening on the page. This distance varies with different styles, but always that distance is there. (And maybe that's what you want.) And by the way, that distance between the writer and the invented third person is often that written sound of writing that I talked about yesterday.
The invented "I" allows the writer to still be in the story, and not outside the story explaining the story, the way the invented "he" or "she" is.
And something mysterious. Since the invented "I" is not the "I" of the writer, the invented "I" gets to feel the tough emotions, while the "I" of the writer watches in an extremely close, if not totally absorbed, personal proximity. The "I" you have created can feel the pain instead of you because you have invented this "I" to do just that: feel it for you on the page. Or at least, the invented "I" can allow the writer to be the character in the invention to feel the pain. In a way it's like therapy. You get to a point where you can talk about yourself experiencing pain as if you were someone else who experienced it.
And to answer the second part of the question: writing fiction like this, dangerous writing, is a scary line to walk. Sometimes reliving the pain is just that. Whether you do it or your first-person narrator does it. Sometimes you can transcend the pain and turn it into understanding. But understanding like that doesn't happen often, and when it does, it is a great treasure.