What is with my(33f) boyfriend’s(31f) ex girlfriend(31f)??

I’ve been with my boyfriend(m, I messed up the title) for about two years. Ten years ago, he was with a girl for a few years off and on. She dumped him and started dating someone right away, he was really hurt and just focused on himself and didn’t really date again. In 8 years or so, I’ve been his only serious girlfriend (he dated someone for two months 4+ years ago).

I first saw her at a party and she kept walking past us and looking at me, then when my boyfriend was alone, she ran over to him and started talking at him. He was very uncomfortable in part because she had barely spoken a word to him since they broke up, despite being in a similar extended friend group. But now here she is.

Somehow she found my letterboxd and started following it. I’ve seen her a few times and when my eyes sweep around the room, she always seems to be looking my way. Last night, I was at an event dancing with my boyfriend and she ran up, hugged him, yelled “glad you came” (it was not her event btw) and ran off. She hovers around a lot, and when I had to say goodbye to someone near her and she jolted and spun around so her back was to me.

She’s married btw.

Wtf is this?

TL;DR: I (33f) have been with my boyfriend (31m) for two years. 10 years ago this girl (31f) dumped him and hasn’t spoken to him really since. Now when she sees us at parties, she makes it a point to get in his face and touch him while not acknowledging me but she gawks at me and somehow found my letterboxed and follows it. wtf?