My fiance lets his friend stay over at our house all the time: Advice?

How would you feel about your boyfriend/soulmate/SO? Bring home a “friend”. Who does drugs? And tells you he’s trying to help her out. But she doesn’t listen to getting help. And you’ve had this talk with him once. But she continues to come into your house. What would you lady’s do in my part? Because I’ve tried telling him in many ways, I don’t want her in my house. And he comes after me. You are telling me why I bring my friends. I mean, my friends asked in advance if I’m not busy. But they don’t spend the night. They come for a quick visit and leave. Unlike his friend comes and stays for a night or two. Mind you, I’m also 5 months pregnant. And I’ve had to go to the hospital twice for stressing over her being here. And doing her stuff around me and pregnant. How can I stop her from coming.???