AITAH for not liking my boyfriend hanging out with his female friend one on one?

I need to get this off my chest. My (25F) boyfriend (26M) and I have been dating for 8 months now. There is this one female friend (26F) who he has been friends with since his college days. She is aware of me (long story) but still invites my boyfriend to see movies late at night, comedy shows, has him catsitting for her (even giving him a copy of her apartment keys), texts him to hang out one on one constantly. He and I are both social people and he has a lot of female friends but those friends do not ask for one on one hangouts every week or two. Since this is my first relationship, I don't know if this is a boundary I should have or if I am being strict and controlling. I do not want to be that girlfriend but this girl especially has talked badly about me and said it was a bad idea to date me at one point. I am tired of feeling stressed and anxious whenever I wait for him to come home from a hangout with her.