Is she really unstable or just crafty? (Kinda long - if you have time to help)?

She is emotionally unstable, beleive me, NOBODY can be stable after having such a troubled past. It may be difficult for you to grasp but I must say, I give you a lot of credit for staying with her throughout everything. She certainly needs some counseling and professional help, because things like this will just be an ongoing pattern. Marrying this other guy will just be another thing she wants to run away from.