How can I stop her from being a party goer?

When I went to a foreign socials one time, I got to meet a so damn gorgeous woman who captures my heart right away. We introduced ourselves, exchanged mobile digits and hit it off. We decided to start dating after one week. For two months of dating subsequently, she officially became my girlfriend. This woman used to party real hard and it was fine with me at first. However, as time goes by, she would go clubbing almost every night and I hate it. Every time I tell her to stop going to parties, she gets mad at me. Some of my friends would come and tell me they saw my girlfriend in a bar which turns out finding myself at a particular bar looking for my stubborn girlfriend. I don’t want her to go to parties because there are tons of dumbass in there but she won’t listen to me. How should I tame her? How can I stop her from going to nightclubs?

Going to nightclubs is definitely a different thing. She has a boyfriend for pete's sake.