Great question. I experienced something similar. I just don't know if it is quite the same way that you experienced it.
My wife also hit a point where the POLF pretty much took over. No more roller coaster, just POLF. She was ready to leave, and was just waiting for the conditions to be right to do so.
In retrospect, the thing about her POLF that eventually helped me to "look inward" was simply the fact that "looking outward" wasn't working and was continuing to fail spectacularly.
For me, "getting it" was not something I was trying to do for myself because it was important to me personally, rather, I was trying to do it in order to make her happy (which in turn would make me feel better about myself). I didn't realize that fact at the time, but with the benefit of hindsight, it is now clear as a bell to me.
I'll be honest with you. Her POLF lasted so long that I gave up too. I really did. And while this may sound horrible, I'm glad I did, because that's what I should have done long ago. Giving up had the effect of me no longer trying to make her happy, and when that happened, I instead, very naturally, started to think about my own life, who I was, what I really wanted, who I wanted to be, what would make me happy, and so on. I started to change and to make decisions based on who I wanted to be and what I wanted in my life. It had nothing, nothing at all, to do with her. As it should be. We cannot heal or control others, only ourselves.
I guess what I'm trying to say is, what I was missing in my life, and in our relationship, was self-respect and self-worth. My value was attached to the perspective of others. As long as that continued, nothing could possibly make me feel worthy and loved, because those things are generated internally, not externally. When I stopped trying to make her happy, and just focused on being a good person instead, everything fell into place. I was able to finally "see her" and "hear her" because there was no longer a personal agenda clogging up the communication pipeline. I was no longer trying to manipulate her into making me feel better about myself, I had that covered, so I could instead focus on her needs and what she was saying to me
I'm still working on it. We just had a conversation last night where she told me she wasn't feeling heard and respected, and until we hashed it out, I really didn't see it or understand it. Those skills take time and lots of mistakes to learn. But at least now, they can be learned, because nothing else is in the way. Had we had the same conversation last year, I think it would have turned into a mess.