I need help

Hi, Im not feeling great since a long time ago.. I feel left down, my boyfriend is acting like a child. I feel like I have to be his mom and looking after him, im in the third trimester he should take care of me but what he does instead is complaining about me and make me cry, says hard things and after hug me like he would apologize and act like nothing happended. Im sick of it; he don't know how deep I wanna run away but I know him he won't be easier to deal with even if we live separately... sometimes I have regrets, I wish I had another man in my life. I wish he would take care of me.. I have to be with his child and acting like I am her parent but im not and he doesn't understand anything, I can't take his responsibilities on my back its too much. I don't know how to be a step-mom and how to act like a girlfriend. I wanna go back to the life I had but with my baby...