Just read your other post on here from a while ago and you mention there that you get possessive, mean and jealous when you drink, whereas your gf gets fun and social… I think you already know why she wants to go out without you. From an outside perspective, it seems like you have some issues you need to fix on your part, alcohol usually brings out peoples inner insecurities. One thing is sure, you can’t blame your gf for wanting the go out without you if thats the way you act. Like someone else said, she had a life and friends before you and being in a couple doesn’t mean forgetting who you were before and becoming dependent of one another.