I don’t want my boyfriend to have female friends anymore

I don’t like my boyfriends female friends at all. We’ve been together for half a year already, 2 out of his 3 friends are girls, and they have never shown any interest in me or even tried to get to know me. His male friends however has friended me on social media. My boyfriend used to have another female friend who he stopped talking to for some reason because he “knew that I didn’t like her”, yet I have said to him that I don’t feel comfortable with any of his female friends but the only one he stopped talking to was her. She also removed him on all social media. My boyfriend talks about his female friends all the time, he brings them up whenever he can and something doesn’t feel right to me. Last night me and my boyfriend were drinking with my friends, he talked about his friend Amanda the entire night. He was texting her and snap chatting her constantly and at the end of the night one of my friends talked about how she missed her boyfriend and that she wanted to have sex with him again, out of the blue my boyfriend says “you know, Amanda likes it rough”. I didn’t understand why he said it because we weren’t even talking about her, we were talking about my friend and her boyfriend. This isn’t the first time I have been suspicious or weirded out about the way my boyfriend talks about his friends. He’s mentioned their sex life multiple times to me and how he encouraged his other friend Matilda to give her boyfriend blowjobs everyday. Both Amanda and Matilda have boyfriends, but Amanda is currently cheating on her boyfriend with some guys she met on dating apps. My boyfriend doesn’t say anything about it, he just shrugged it off like it’s what she does. I don’t like any of them and I don’t want my boyfriend to be close to them anymore, the best for me would be if he cut them both off. The thing is that without them he doesn’t have any friends who stays in contact or cares about him. But I don’t really trust them and for some reason I don’t trust my boyfriends intentions completely when he talks about them like that. I’m not sure how to break it to him, when I first told him in the beginning of our relationship ship that I was uncomfortable with his and Matilda’s friendship he was visibly upset and said “not again”. Apparently this happened with his ex too, she made him cut off some of his female friends because she felt the same way I do. I want to be comfortable with his friends and I don’t really have a problem with friends of the opposite gender, but I don’t like this and I can’t seem to get used to their relationships either.