Girl best friends?

My boyfriend two best friends are girls, both of them have boyfriends. The blonde one is not very mentally stable and once threatened my boyfriend with self harm because of a fight she had with her own boyfriend. She then cussed him out and told him to leave her alone when he tried to comfort her. She hasn’t made any effort to get to know me, when I tried to become friends with her she ignored me. His other girl friend hasn’t bothered to get to know me either. This girl has cheated on both of her partners. My problem with his female friends is that they had zero boundaries when me and my boyfriend got together. I had to tell him to stop talking to them so much because it was uncomfortable to me, I almost stopped dating him because of how much he was talking to his blonde friend. What bothers me is how much attention he gave her and how he would always talk about her, she also kinda looks like his ex. Their relationship has always made me uncomfortable, it’s better now but it doesn’t feel right that I had to tell him to take a step back and that their friendship was inappropriate when their both in relationships. My boyfriend never really set any clear boundaries with his female friends when we got together which bothers me. He made me feel insane and jealous when I wanted him to stop talking about his friend so much because I honestly felt like he liked her too much for it to only be platonic. He talks about them sometimes in sexual context. He asks his female friends about their sexual relationship with their boyfriends, he told me that he made his one friend promise her boyfriend weekly blowjobs. And how his other friend likes to be choked during sex, she “likes it rough” etc. I never talk about my friends in that way. He has apparently also asked for and given sex advice. He told me that he discussed our sex life with his friend and told her that he wanted tips on how to spice things up between us. He didn’t even ask me, he went to her first and then told me what her advice was. I don’t want my boyfriend to talk to his girl friends about sex at all.

In the early stages of our relationship he talked about the blonde girl non stop and would bring her up any time he got the chance to. I never mentioned my friends nearly as much as he mentioned her. It felt like I was his friend and she was his girlfriend the way he talked about her non stop. When I told him that their closeness caused me discomfort, he got very upset and told me that he would “never ever stop talking to her” because she is his best friend and the only person that understands him. This was in the very beginning of our relationship and what made me question his intentions with her.

He has contact with his friends on snapchat almost daily. The thing is that I never see them talk to each other, he seems to always respond to them when i’m asleep or when i’m not present. When he’s with me the girls never send pictures of themselves, it’s mostly the roof or black pictures. It seems like he doesn’t talk to them when he’s with me. It’s been 7 months with my boyfriend and I don’t seem to get any more comfortable with their friendship. I try not to care because I don’t want to seem controlling, but I don’t like how close they were and that they “hide” their friendship from me. I know that I can’t ask him to stop talking to his female friends because of me, but I just wished that our relationship started out different and that he listened to how I felt about his friends, because now I still can’t seem to shake this weird feeling off.