I’m in total agreement with Jessekim. The last thing you want is for her to think you don’t trust her. You didn’t say how long you’ve been together, and I might ask her why she wants to go in the first place especially without you. There is nothing wrong with her hanging out with friends, but she should also take your feelings into account, and realize you’re not exactly cool with it. Ask if you can go too, and if she says, “no,” then I would raise some questions. What is considered controlling? Well, telling her that she’s not going to do something because you said so. Trying to plan someone’s life for them. Demanding things, like dinner on the table at 5:00. That kind of stuff I think is way too controlling. There are other ways to get your point across, and it all boils down to communication. Every good relationship has it, and sometimes you have to just leave it up to them to make the right choice.