If you had a person telling you something is off every week, it's be hard not to take it personally. Her inability to also call it quits even though she is evidently unhappy as well keeps you thinking if only you did this, if only you do that. If only you were this, if you only you were that.
I want to share some of the wisest words I've been given about relationships:
"You don't have to marry everyone you sleep with."
You didn't waste your life. I am hoping you got to enjoy time getting to know the kids, yourself with kids. That maybe your picker is off, and choose broken birds. You are really at a crossroads here. One, where you realize you want to be loved for who you are, and supported and cherished, and realize it's not with this person. Or one, that feels familiar that you believe you must see to the crappy end, which is what you've been doing your whole life.
A person can mask easily for two years. But it is impossible to keep it up for much longer. And, what you are seeing is really her now. She is showing you who she is, but you are hoping that it will magically work after you tie the knot. What you are experiencing now is just the tip of the iceberg. There are so many layers of "you just don't work together." Couples counseling will never fix her "severe anxiety, depression, and trust issues." That's not your job. She is in NO PLACE to marry.
Want more for yourself. It is out there when you are ready to accept it.