How do I get my girlfriend to stop partying so much?

Answer 1

You could directly ask her to stop,

or if you don't like that approach then try to come up with plans for the two of you to do together as an alternative to partying. For example, if it's a Saturday night and she normally likes to go clubbing, you could ask her if she wants to go out to dinner or something instead. Try to focus her attention on other things and maybe she;ll eventually come out of her partying addiction.