What do you have to lose?? If you feel totally comfortable with them, then I would go and since they invited you then I say go for it!!
Really, what do you have to lose.. the worse that could happen is that she will move thing along faster, which might be better for your emotionally not to be hanging out anymore, or it will force her to maybe think about what she is doing..
tal
me: 37 H: 44 Married for 18 years this june S7 S3 porn issues, and much more... since 7/06
Happiness can be found, even in the darkest of times, if one only remembers to turn on the light.