What should I do about my Ex-Girlfriend?

I'm going to just tell you all this straight up. 2 years ago my Ex-Girlfriend of 4 years left me, essentially because her friend group enticed her to "enjoy college single". From the start of our break up till honestly now, she has dragged my heart through hell and back by keeping me and my hopes around and alive. She has dated 2 guys since (currently with one now) but always seems to keep in touch with me and essentially tug me back JUST as I'm ready to move on. There were FaceTimes and phone calls in the beginning. Meeting up and hanging out, and text message check ups every other week. It was like she would pop back in just to get my hopes up, then disappear for another few weeks while me and my heart wallowed in a shattered mess.
With all this, I went through the deepest, darkest depression of my life. Sought out councilors, psychiatrists, you name it. AND FINALLY (recently as well) I conquered the art of self-love. I began to chase my dreams, improve MY OWN life and happiness everyday, and eventually, became happy again. I have now (in a sense) moved on. I could care less whether I get her back or not. Life is good where I'm at and I can't wait to conquer the world! The only problem now is, I'm sitting on top of this airplane soaring high towards my dreams, while I'm watching her crash and burn.
Now why is this a problem?? Isn't this what any Ex wishes for? To end up better off than the one who dumped them? It's like I reached the point where I know, and she knows, that leaving me was a mistake. Since the break up, she has fallen deep into drugs, failed out of college, and now, at 20 YEARS OLD, she has an unplanned pregnancy on the way with a guy I TRULY don't believe she wants to spend the rest of her life with. But why do I care??
I'm honestly really not sure. I know it's not my problem and it shouldn't affect my life... but it just hurts me to see someone who used to be such a beautiful soul turn into such a mess. She was my first love. My best friend, and from what I thought (and truthfully still ponder) my soul mate. And now I can't help but look at her and label her as a Loser.
I want to help her so bad. I've tried multiple times getting her to take the right path. Away from all these abusive relationships she's been through, the drugs, the partying. And I know deep down, there's still the beautiful girl I met in there somewhere, ready to achieve her dreams like she was in high school. I just don't know what to do to get that out of her...
It gnaws at me everyday that I believe our relationship was "lost love". That we were "meant to be" and I really should be there for her while we both conquer life. But I know it's just a dream and my thoughts playing tricks on me, I just don't really know how to get rid of them?

P.S. And I know it sounds like I'm just a hopeless Ex who can't just let go, but with the amount of times she has fought to keep me around throughout these years, I can't help but feel that she still loves me too.