Espoir,
Welcome to PC! I agree with Perna as usual. Unless I misunderstood your posting you are assuming that your boyfriend is lying to his ex about the state of your relationship.
First of all, that may not be the case. His ex may just be a friend in need. Once you’ve had a relationship with someone, those feeling don’t just disappear. If this was a serious relationship he probably still cares about her. Not in the same why he did when they were together, but as a friend.
Secondly, in my opinion she is very mentally ill. Even though, based upon what you’ve posted and I am no expert, she may not be suicidal, she’s still SCREAMING for help. Your boyfriend seems to be the only one listening. He’s probably afraid that if he ignores her she really will do something to harm herself.
She sounds like a class A manipulator. I am dealing with a similar problem, although not on the same level you are and Clyde (from Clyde’s corner) gave me some excellent links.
http://www.wikihow.com/Deal-With-Impossible-People
http://www.rickross.com/reference/br...washing11.html
http://www.egyptsearch.com/forums/ul...3;t=004171;p=1
Finally, I’d like to suggest that you issue is less about her, and more about trust in your boyfriend. If this relationship is serious, you really have to deal with that issue. Has he given you any reason to distrust him other than this situation? While this situation is the one that is the most obvious at the moment, I would really explore the source of the distrust.
I wish you all the very best of luck.