Sleeper, From your posts, I can tell you are a good dad. X obviously hasn't detached. I guess that's an understatement.
Have you considered introducing her to your fiancee? I know this seems stressful but perhaps she will calm down when she has a better sense of who this person is.
As you know, kids are growing up fast and before you know it, X will be in rearview mirror
M: 16 years Bomb 4/07 OW 20s long gone Divorced 11/09 I remarried New Guy Cooperative r w/X regarding D