you wrote: "We went on a trip to Boston in April and had a great time although she planned all the activiites. We had a trip planned to Canada for Memorial Day weekend. The day before the trip she invites to her house for dinner and tells me that she is going on the trip but I am not because her daughter is now going. She also asked me to leave so she could pack after 45 mins."
If anyone did that to me I would be out of their life without fanfare. How sad that you're still giving her power and wasting your time by trying to analyze her. Whether she's a sociopath or not is irrelevant. The bottom line is this: all she has for you is pain.