Am I wrong to still feel hurt by what my wife did?

My wife and I met back in college 9 years ago and we've had our ups and downs. Overall pretty good. We dated steadily after meeting in the dorm. When we got serious I asked her to make it exclusive and she was very excited. Nevertheless, she went on what she called a last date with a guy who lived on the lowest floor in the dorm. He was a jock kind of guy and maybe a frat guy. He ended up getting her to spend the night in his room during which she admitted she gave him . Long story short, she told me a few weeks later, she told me what had happened, though with details that still stick in my head to this day. I forgave and we stayed together, though I dealt with nasty looks and jokes from him for the rest of the year. What bothers me now is when the story of our early time together comes up in conversation with others, she tells it like the whole thing with that guy, minus the details, was just some fun she had and no big deal. She does not seem to see that it did matter to me a lot, and that I was hurt that she did that so early on. I am not angry that she did that, but that to this day she sees it as sowing her oats and girl-power kind of stuff, while I thought it was a big deal (and she seemed to at the time). Should I just ignore how she sees it and forget it all? Or do I raise the issue again at the risk of bringing up what is admittedly a long ago issue in an otherwise great marriage?