My boyfriend (29M) and I (25F) have been together for 2 years. We recently moved to a new city for his school. He started an environmental science masters program after the new year and immediately become close with his female classmate. She has a sort of loudest-one-in-the-room personality and I have a hard time feeling comfortable with her presence. She tells him about her dating life, her family, her past relationship, her roomate. Mostly dating life. She used to play tennis in college, so he started inviting her to join him and some others for their Sunday afternoon tennis games. She seems to be texting him quite often (daily, with occasional phone calls too) and he's assured me they are only friends. He doesn't hide their friendship from me.
But some things she has done just strike me as...weird? For one, she is so so enthusiastic about everything. Like so bubbly. She was getting her hair done and messaged him that she was getting layers and highlights. I found that a bit odd because it's appearance based. She asked him to share a digital subscription so they could do puzzle games together (he didn't agree but saw that as a non-threatening ask). They went to a classmate's birthday at a dive bar and he showed me a group photo where she was leaning into him and I know it was probably just a natural movement for the photo but it bothered me. She makes granola and sometimes brings him and her other friends some to class. Stuff like that where she's not necessarily being flirty but definatlely orienting towards him a lot. She peer reviewed his paper and some of her comments were just like "wooohooo book worm" and "you should be so proud of this!!"
There have been chances for me to meet her but it hasn't happened yet. How can I feel OK with this person? I've talked about this with my partner and he has assured me there's nothing to worry about. I truly think he means well, it's her I don't trust.
TLDR - My boyfriend has a new female friend. She is very bubbly and cheerleader-y and her presence bothers me. How can be more OK with her without driving a wedge in our relationship?