I'm really big on communicating and looking for middle ground and such, but holy crap... I've looked through your past posts about this girl and I agree with nycindie. She quite obviously does not want you to be with your boyfriend, so she's going to attempt to exert as much control as she can over that relationship.
I'd issue the counter-ultimatum.... stop trying to control my other relationships. If that's an issue, you know where the door is.
Me - 37 years old male, father of three wonderful girls.
Curls - 33 years old female, My wife of fifteen years.
Freckles - 22 years old female, our awesome girlfriend.