My Secret with My Student Is Over

I'm a professor in my forties, and I've always prided myself on being professional. But there was this student, a bright young woman in her twenties who joined my class halfway through the semester. She was curious, engaged, and I found myself drawn to her. Not just as a teacher, but... well, differently. It started with small things, flirting a bit too much after class ended, giving her more attention than I should have. One night, we were alone in my office going over some final project notes when the line blurred. She was so close to me physically and emotionally that all rational thought seemed to vanish. There was no turning back once she whispered how she felt about me, confused but drawn like a moth to flame. We ended up crossing boundaries, engaging in secret DDLG dynamics over text messages. We called each other Daddy and Princess. It felt taboo, thrilling, wrong... but oh so right for us at that moment. She would send pictures of herself in outfits I liked, and we'd chat late into the night about everything from homework to more adult fantasies. But then things went too far one day when she showed up unexpectedly at my apartment while my wife was out running errands. The guilt hit me hard once reality set in. Our dynamic had become toxic, affecting her studies negatively and causing major stress in my marriage. We decided to cut ties fully but agreed to stay friends. It's been months since we've talked beyond basic academic exchanges now. I know it was a mistake from the start but sometimes you can't help who your heart leads you towards even if reason screams otherwise.