Saw my Ex at an intersection and need to get over it.

TLDR: I saw my toxic ex-girlfriend in traffic today and she texted me something hurtful to acknowledge she saw me. Why does this bother me so much?

We broke up after 2 years in December of last year. Zero regrets. She was manipulative, jealous, controlling and a little bit racist. But she’s hot and I’m shallow (I’m working on it). That’s probably the only reason we lasted as long as we did. That, and covid took seeing other people off the table way too early in our relationship. So. Zero regrets, ending that relationship was absolutely the right thing.

Anyway, I was making a left turn today, waiting for oncoming traffic, and guess who was the oncoming traffic. Of course it was. Driving the car I bought for her when she was down on her luck and I wanted to be some goddam hero. She waved and I nodded. I had a female friend in my car with me. Just a friend, but a good friend, and a friend she should have recognized but perhaps didn’t because she’s cut and colored her hair since my ex intentionally cut herself off from my entire social circle upon our breakup nearly a year ago. My friend is a little overweight, now sports a boyish haircut, which I think she really owns and rocks it. But, I wouldn’t date her romantically. My ex texted me “That woman suits you”. Thats it. That’s all she texted. I was pissed all afternoon about it. I’m having a hard time putting my finger on exactly why. And I’m pissed at myself for letting her still get to me. I don’t know if I need someone to explain me to me, or just sympathy, or tell me something to just help me do the obvious thing I need to do: Let That Shit Go and Do Not Fucking Engage.