I'm a freshman in college and I've started dating this girl for around 2 months. She respects me a lot and goes out of her way to do things for me (even cooks stuff for me). We often have intellectual conversations with each other, and is she the most rational female I have met yet. That said, she recently acted kinda naive. I don't know if this comes from her inexperience in dating or what (she was a virgin).

She told me about how she wants to go on a vacation with a friend. This person is a guy. Now, she has beta orbiters who she uses from time to time for free help with assignments. I know them and they are pathetic and not a threat to me. But I don't know this guy, he's some online friend from her home country. Besides that, if a girl I date goes on vacation with another guy she is not my girlfriend. Right now, it's winter break and we're both not on campus. I wanna take this as an opportunity to make boundaries clear and tell her that it is disrespectful to me as a man for her to go travel with a guy. I don't know if I should tell her this in person when I see her or now over the phone. I want to set boundaries, but I also don't want it to come off as insecure/needy if I just suddenly brought this up. How do I go about this?