Narcissistic family

Hello, I don’t usually like to put my personal life on social media, but i need advice. I dont see my therapist for a few more weeks and I really need help now. I have been with my boyfriend for three years now. We are engaged, we have a house (rent), a cat, and i am currently 17 weeks pregnant. It all starts with his mom and step dad and sister. They are all narcissistic people. I have read up on this and have even talked to another one of my boyfriends relatives and its true. They have bad mouthed me since day one, they always say i need to do this i need to do that, they questioned why i hadn’t posted about my pregnancy yet, they try to control me. They always say they are “done” with my SO. Then turn around and throw money in his face so they can weasel their way back in. Its to the point where i want to leave my SO because he will not cut them off and i cannot handle them in my life. I know that is bad of me for even asking him to do... but i have put up with this for three years now and they have threatened me with taking my child away from me. I am so stressed to the point of breaking down every day. I dont want them in my life, i dont want them in my childs life. I feel like I’m living in a nightmare that i wont wake up from. I dont want to leave my SO, but i dont know what else to do. Someone please give me advice. Please.