For me, hot brunette in her early 20s, American history teacher.
She was married.
She was incredibly friendly to me; a lot of her political views aligned with mine, she legitimately cared about me, and we would have discussions outside of class in the context of school related things.
A friend of mine said he fucked her, but he was known for talking bs about who he fucked, was a 5-6/10, had a lot of confidence.
She also happened to reveal that she was pregnant a few months later from her husband.
Regardless of what actually happened, whether it was legitimately her child or her husband got cucked by my friend, I remember as a high schooler connecting the dots, and not talking to her at all from that point on. She later confronted me angrily wondering what was going on, and our interactions weren't the same.