I reallyyy need feedback

So my boyfriend and I recently met this girl (from doing a show with her in theatre) who is absolutely GORGEOUS and I really liked her and we became friends. So I noticed that she started making flirty comments towards my boyfriend and I got pretty upset but I thought that I was just overreacting because she’s really nice so I didn’t think she would do anything like that. Anyways I was finally starting to feel better about it but she just made changed her profile picture on Facebook to a picture of the two of them... they’re not even close and she knows we’re dating so I don’t know why she did that. I’m really upset about it because it looks like they’re dating now :( I mean I trust my boyfriend completely but it stressed me out when someone so beautiful is coming on to him you know :( I don’t know what to do about it

UPDATE

So she posted on Instagram about our show and she made the cover photo her and my boyfriend.... and my boyfriend COMMENTED!!!! He said “Had so much fun with you!” Like WHY in the world would he do that when he already knew I was upset!!! I don’t want him to think I’m a crazy/jealous/controlling/etc. girlfriend but I really feel like I need to say something because I’m so upset about it.