Is it bad that I fantasized about one of my girlfriend's friends?

"Honestly, I don’t think it makes you a bad person. Fantasies can pop up unexpectedly, and they don’t always mean something deeper. What matters is how you handle it in real life, and the fact that you felt guilty shows you care about your relationship. Try not to beat yourself up—our minds wander sometimes. If it bothers you, maybe reflect on why it happened, but don’t let it define you."