Boyfriend

So 2 of my friends added my boyfriend on Facebook and he added another, I'm okay with him being friends with 2 of my friends on and outside of Facebook but I don't want him to be friends with the other one because she causes so much shit between people and I asked her to delete him off Facebook and she did. Also, my boyfriends only friend killed himself earlier this year and my two other friends are good friends with him, he confides in them all the time (as well as me) if he needs to and they're always there for each other and I'm happy that he gets on with them both but do you think I am wrong for not wanting him to be friends with the other girl? Because all I can feel is guilty and upset that I got her to delete him off Facebook because I know how she is. Although me and my boyfriend have been together for almost a year and we talk about everything together, I feel really uncomfortable talking about this situation with him.