I (23f) have been best friends with this girl since we were 13. We were incredibly close—like family. A couple of years ago, a guy she knew messaged her saying he wanted to talk to me. She encouraged it, said he was sweet, and told me to go for it.

So I did. We started talking, I liked him, and we eventually started dating. It was only after that she told me they had almost dated once before, but she said she turned him down and didn’t like him anymore.

Later, she told me he had a long, toxic on-again/off-again relationship with a girl he’d been with for six years, and during the off periods, he’d date other people. Basically, I was one of those people. Still, I liked him and kept seeing him.

Eventually, when I told him I wasn’t ready to sleep with him, he ghosted me—and not long after, he got back with the same ex. I was heartbroken. I cried in front of my best friend for weeks. She sat with me, consoled me, told me he was trash. At no point did she say she had any feelings for him.

Fast forward about two years. He was still dating that same girl when he messaged her this time. She told me it was just friendly, that he was being annoying and it was nothing. Then they started texting constantly. He sent her gifts. Told her he liked her. And then—surprise—he broke up with his girlfriend again.

Next thing I know, he’s spending the night at our place, and I find out they’re together. I didn’t even hear it from her—she just let me find out. When I confronted her, she admitted it and said, “I’ve always liked him, I just didn’t want to say anything before.”

I was stunned. She watched me fall apart over this guy. Knew exactly how much he hurt me. And then still went and did this.

I cut her off. She’s been telling mutual friends that I’m being childish and overreacting, and some of them seem to agree.

So… AITA for ending a 13-year friendship over this?