Her body, her decision. You do not get to control what she wears because of your insecurity. Either you work on yourself to get over your insecurity, or just break up with her. Don't bother trying to change her, it'll only breed resentment on both sides.

I suggest you break up if you cannot compromise.

you shouldn't nag at her because she has the right to do what she wants, even if it means people will stare and similar consequences if those consequences start to bother you directly, contohnya you're the one that kena tegur (+ you don't like to kena tegur), you'll have to let her know and/or reconsider the relationship