My ex fiance wants me back in her life.

I'm at a loss. I was engaged to be married to what I thought was the most wonderful person in the world. She and I were perfect. We were BEST FRIENDS.
Her ex husband is a mean and controlling person and became furious when she and I began seeing one another. And became violent against me when he discovered we were to be married. To make a long story short, she felt pressure from him to reenter a relationship with him and broke it off with me several times...back and forth between her ex husband and me. Very hurt to say the least...I all but went insane during this time.
Now, it gets worse. During all this hell, she created an online dating account and met the greatest con artist ever. I'll call him DICK. Dick projected him self as a Godly man, stable (wealthy) and full of potential. She dumped me for this guy DICK who turns out to be homeless, jobless, and car less. She moved him into her home within a week of meeting DICK...she discovered his B.S, but tried to make it work. After a few weeks past, DICK moved his two kids into her home. Everyone warned her that he has done this to several women in the past...even Dick's mother told her that he was a POS.
After 8 months had past and after he drained her of everything, DICK was kicked to the curb along with his kids.
During the 8 months, I had zero contact with her...even though she stalked me. One day, I receive a knock on my door. It was her. She said she loved me and missed me so much that she believed her heart would stop if she didn't see me. She and I began to talk and she confessed that the reason she dumped me was because her ex was threatening her and me if she wouldn't stay. She claims the reason she began a relationship with DICK was to prove to her ex that he would not control her and to protect me...got me out of the spotlight so to speak.
Now the kicker, she is pregnant by DICK.
She wants me back. Cannot live without me. I am the love of her life. I am her everything. She is so sorry for denying her love for me. She cried every day and night for me. I am the only man she has ever loved...excetra.
Now, her ex has had a "come apart" because she is pregnant and wanting me again. His ass is going to jail....finally. On the other hand, DICK is putting pressure on her to be with him. All this combined, now she wants to be left alone by everyone. So, after 2 months of being in each other's lives...I am cast aside.
I love her...I truly do. But, I don't know what to do. I feel as though she love me, but I also feel like she may be using my love to benefit herself during this time of struggle.
Her ex doesn't want me around his son. DICK doesn't want me to be around his soon to be child. Yet, neither of these bastards want to do anything to help her.
I don't want her to be stressed out for her and the baby's sake...should I be her best friend. ...should I walk away...should I be mad and tell her to leave me alone and lose the love of my life? I am in love...but look at this tangled web of craziness. I am at a loss. FROM MY HEART, I AM SCREAMING FOR HELP.