Why would an ex read your old letters

First let me start wit this preemptive caveat; I am/do not actively track friend/lover emails. I have a biz account I do track reads and link clicks for promotions I send off. I met this woman a couple years back via a business acquaintance so we started our initial discussions on the biz email. Soon we started spending every day together and speaking in person or communicating via phone/text. So the tracked emails referenced in this thread are from later on when I returned to emailing her a few times post break up from the only email I had. That said. We had a horrible break-up during what I realize was a melt-down or episode on her part. Much/most of the relationship was dealing with serious emotional issues/limitation she had, I'd been used to being pushed away and dealt with it fine but this was just a cruel desperate night precipitated by her. I later discovered she may suffer from Bipolar and/or Borderline Personality Disorder, both of which are characterized by rages where they push the very people they love the most by attacking them mercilessly with the things they learned about them. I did not respond well and struck back cruelly as well, to my everlasting shame. But I'd had enough of over a year of being pushed away and distanced and the things she said were horrible. I am supposing she expected me to be 'the strong one' and once again reach out and say some beautiful healing things but I did not. I ignored her. I walked out of places when I saw her, I walked by her in the street, I never texted or called again and if mutual acquaintance asked how I was I always said find so glad to be gone from her. Clearly she had gone into a freefall based not on just how she went off on me but how she just disappeared from mutual social circle/places, I heard she was seen stumbing drunk from bars, she started dating some dive bar slimebag (a girl who can have whom she wants). So I got worried and reached out with a letter apologizing for my words during the horrid night and letting her know I wished her the best. I did make clear I'd moved on and would not reach out again so gave her no place to reach back I ended up in fact reaching out 3 more times over 4 months, all the same gist; non accusatory, no pining, just letting her know I had and always would care for her. Mostly because I got she was not doing well and dnt' want her to think on top of all she was dealing with that I too hated her or that she'd lost my caring which I knew was important to her. So Recently I accessed my Read Receipts Folder to check a recent campaign and there are dozens from her. She has read everything I sent over and over. In fact one emial I sent when we were seeing each other which she scoffed at when we broke up she in fact read 20 times in three days when I sent. The most recent one, she read 3x in the wee hours after I passed her on the street. Then she read it again 2 weeks later from 11am to 5am over and over. THen she stopped in to 'our' place where she'd not been for months only to just miss me. Then she read it over and over until 5am again. So I am conflicted. I am still somehow greatly connected and caring for her but managed to move on and go no contact and live my life even though part of me was sure she'd 'messed up' and pushed me away w/o thinking. I sent the emails really so I didnt' worry my words contributed to her pain/spiral. Yet her I am finding out she is clearly as far as I can tell as connected to us and me as I am/was. I turned off the read receipts for her account so I don't have to torture myself and since it is supposed to be just for business. Yet Pandora's Box is open for me now. If you are a lady would you open caring/loving letters from a guy you dumped/broke-up with 1/2 year later? Not once but over and over into the wee hours of the day? Am I just grasping at straws here or odes this means something. Note even when we were together she had no agency and could never put herself on the line, make the first accetionate move or word so I'm pretty sure after being body-slammed and then ignored for 6 months reachinc out to me first even after the emails would be hard. Thus I am Confused in Denver...

Well she has in her own lack-of-agency way tried to put herself in front of me at no risk to herself. This is the hallmark of how she deals with me. I'm 99% sure she'll try again. She's just not going to do anything that makes it clear she is the one reconnecting. Not replying. Not stopping by where we are to say hi. She'll do what she did; stop in so I can see her. She was incapable of even reaching out to take my hands in affection unless I did first then she lit up like a Christmas tree I've considered Narcissist but she doesn't fit most of that. Bipolar confirmed, likely Borderline, in any event damaged (as per her beyond repair) and terrified of actual caring love since she came from abusive father who hit and demeaned her. So less narcissist than just never learned to love or be loved but wants it. I on the other hand did. I'm not a rescuer or white knight, I got/get sucked in just simply because I care/cared deeply. I meet very few women in my life I'm drawn to so when I do I stay connected pretty strongly. And no, none of them needed rescuing before. I told her as well there is a difference between being drawn to people who need rescuing and being drawn to someone who turns out to need, if not rescuing, a ton of TLC and support and then giving it. I'm clear on the difference. For now just letting the recent events sit; she found a way to show up a couple nights after reading the latest email again at 'our place' which she does not frequent anymore. I happened to show up later than I normally do (pretty sure she'd end up doing just what she did from knowing her well) and we bumped into each other on the way out, she smiled and said 'hi' I smiled and said 'hi' and sat down. That is her way of 'making something happen'. It was a nice moment since first civil/affectionate/acknowledgement moment in 7 months but I'm utterly unwilling to do anything else. If she figured herself/me/us out than she knows how to find me. BTW it was not an exciting or hurtful time, just the last night. I'm sure she is still going through whatever hell she did or worse, and one hallmark of her being with me was how calm and happy and safe she felt (her words and also clear as day on her face). So if anything she might be reliving feeling that.

BTW; not sure if I care if she is 'available' as much as perhaps mending fences as it was hugely traumatizing for me and I think her. I'd like her in my life again I think, I'm 99% sure I dont' want a romantic future with her as it would be a lifelong challenge.