Often times underlying alcoholism is a personality disorder, or mental illness. Considering her familial upbringing, and her actions, i would guess (just a guess) a PD. The good side of a PD is charisma, energy, sense of humor, appearance to be very loving, interesting, charming. attractive (especially if dealing with a narcissist). They are a perfect fit in every way, you like the exact same things!. They can be very fascinating. Then things change......and you end up with a nightmare you don't recognize. Add in alcoholism and addiction and its simply an unmanageable situation. Why we stay I figure is we just keep trying to row back upstream, ,and get them back to what they once were. The attraction remains due to our memories, and when you are offered a day or two of the "old person" here and there.
You probably had real chemistry with this woman. You can't fault yourself for remembering that feeling. You don't really know what's going on with her at all. You are left to your imagination via photos on FB. That'a why its suggested to dump all social media and not look ever. FB is a
PR machine, the ultimate catfish. Realistically, you didn't exit the relationship and her behavior took a 180. She is an unstable alcoholic who is now a single mother. I recall she had a very hard time holding down a job, could not support herself, and required another person to manage her life. A baby isn't a welcome addition to a person like this. What a mess.