Ex’s current bf or fiance idk, pinged me on linkedin, AITAH here

I (M) had a crush on a girl I knew from school. We eventually started dating while we were in different universities. Early on, she told me she felt the safest, happiest, and most comfortable around me. I later realised had different expectations going into the relationship, but that wasn’t what ended it. What actually ended things was a nasty incident. A mutual friend “K” (her college classmate who had previously tried to pursue her and been rejected) got jealous when he found out we were together. With the help of her “best friend,” he created a fake Reddit account using her details and posted her phone number online, advertising her as a call girl/prostitute. At the time, I was already sensing she wasn’t as invested as I was, but when I heard about the posts, I felt terrible for her. I investigated, heard from K that it was a mutual friend “B” who also had a crush on her), and reached out to warn her. I told her she should file a police complaint, or I would. Instead of taking the suggestion, she and her family immediately blamed me. She started telling people I was responsible, her brother interrogated me out of suspicions, and the rumours spread fast in our hometown. I became an outcast among our age group, everyone had their own exaggerated version of the story. Her parents, who only vaguely knew we were dating, repeatedly called my house demanding to know why I would do something like that. It got so bad I couldn’t go home for months. Eventually, I confronted K, found out he was the one doing it, had a major clash with him, and gathered proof of what he and her best friend had done. He begged me not to go legal, saying it would ruin his plans to move abroad (passport verification issues), so I dropped it. The most infuriating part? Even after I showed her clear evidence, she never cut ties with any of them. K remained a close “family friend,” her best friend (who helped K) still regularly crashes at her house and chats with her parents like nothing happened, and she stayed close with all of them. We cut contact shortly after all this. Fast forward two years. Out of nowhere, her current boyfriend (now fiancé, apparently they live together and are planning to marry) found me on LinkedIn. He came across an old shared Pinterest board we made during our relationship (just cute couple pins), saw my profile linked to it, tracked me down, and started messaging me invasive questions: “Did you two actually date? Did you have sex?” I screenshotted everything and sent it to her, asking what the hell was going on. Her response? This was somehow my fault too, her fiancé “would never do something like this” unless I had provoked him in some way. In the same conversation, I asked why she was still best friends with the people who actually harmed her while blaming me for it all those years ago. She turned it around, saying I “never stood up for her” and that my parents had been rude to her (they weren’t, they simply didn’t believe her accusations because they know I’d never do anything that sneaky). I reminded her that I did stand up for her: I investigated, confronted the real culprit, got proof, and gave her the chance to take legal action, all while she was actively blaming me and spreading rumours. Why would I (or my family) go all-out defending someone who was throwing me under the bus? She blocked me after that. I felt instant relief, but also disgusted that I ever had feelings for someone who could blame-shift and rewrite reality like this. I truly dodged a bullet.