Relationship Problem

[RustShack]

Say you've been with a girl for awhile, and your about to move in together. She goes to the bars with a few friends once every week or two and doesn't like you to come with. Her friend meets a guy and they start hanging out with his friends, and after a few weeks your girlfriend is going to a movie alone with one of the friends but she says its "just as friends". What would you do or think?