What to do when a child chooses one parent over the other

My end has been unstable. I have moved several times in her life and he's stayed put. She's never seemed to have issues with changing homes. Humans adapt to change. 

So she has almost always been a daddy's girl. He gives in to her. Let's her have sweets and pop and play on the phone all day and video games. Etc. 

I am the bad parent whom lets her have one sweet or junk food a day and only natural juices, milk, water. Etc. I do not always give in to her, I am trying to make her a good person. And grow up with boundaries and such. So I have settled with a new man. Married. Have a nice house. She has her own room. And a baby brother on the way. 

She's thrilled about that. 

    Now months ago she started crying whenever it was my turn to get her. And I started bribing her with toys to come with me. And I slowly stopped and she got back to the point she was coming with me just fine. 

And now again she is throwing horrible fits. 

Tonight I picked her up and she started screaming bloody murder. I mean like I was putting fire to her skin. I've never experienced this before. Just the crying. This was something new all together. I tried to calm her and to talk to her and tell her it was not ok to behave this way nor to treat mommy like this. I missed her and loved her and it's my turn to see her. 

So she persists to scream and try and run back to him and she bites me when I wouldn't let go. And I wasn't grasping her hard to hurt her. But she kept biting me. 

And at this point I'd had enough. I'm 51/2 months pregnant and started breaking down and told her father to take her that I was done. I shouldn't be made to feel like this everytine I see her. It is breaking my soul to see her act like I'm the devil. I barley raise my voice to her ever. She is not neglected or mistreated. I spoil her in my own way without candy and soda. I'm at the point where I am going to let her live with him for good. And I sound horrible for saying that but I don't know what to do. She's my everything. And I feel so low that she doesn't love me. She even crys for her dads newest gf that's been in her life a few weeks. I'm so lost