Don't wanna lose my Girlfriend - help?

I stopped at 'She said she couldn't promise she wouldn't do anything with him because it would be prom night and alcohol would be involved in the equation''.... i think you should lose her before you get hurt. It doesn't matter if she kept a promise to another guy before, she should have asked you to the prom. She is up to something, you can either wait and see what happens potentially risking heart pains or just leave her..