You let her tell you to your face you are "too boring??" You WIMP! Don't stand up for that sh#t! Either let her go or tell her to quit treating you like that.
I think I have a plan for you. If, at this party you see her and she wants to cuddle, you can say "I'm not sure, are you gonna be an a$$hole again and call me "boring"?" If she tells you to p#ss off then so what? If not then cuddle with her and don't talk very much and let her whine "why aren't you talking?" Silence really drives them crazy.
Good luck. But i would not waste much more time with her after this night anyway.
"You are a reflection of your friends (and lovers)"