Splitting while pregnant

I never thought i would be in this situation, i have a man who ive been with for a year. We started out as besties and then moved in together. Im pregnant with a boy witch is what we both wanted well this relationship ended as soon as it began. He has a wife who he hasnt divorced and a step daughter and bio daughter with her, he always says he’s daughters are first and i get it my two girls are my life too but i never mention to him that they come above him even tho I know they do. We have been having problems alot lately to the point where he tells me to leave and didnt even get me a candy for Christmas, well i feel so alone i dont know why he dose love me? I didnt think getting pregnant would fix things but i also didnt think i would be suffering alone during this time. I want to leave be strong enough to walk away but i cant seem to go; i want him to need me like i feel i need him. I dont want to be pregnant and alone: but if i do end up leaving i want him out of my life forever. I guess i just wanted to rant, if anyone wants to talk? I also have the worst pregnancy symptoms witch also doesn’t help, and my ob prescribed zoloft witch makes me feel worse rather than better