I’m struggling with a boundary issue involving my girlfriend and her male friend

My girlfriend and I have been together for several years. I trust her, and I'm completely okay with her having male friends. However, there's one male friend I've been uncomfortable with because their interactions have gradually become more personal.

She has never hidden this guy from me. She has told me that he helps her a lot, and I was completely fine with that. Before Raksha Bandhan, he told her face-to-face that he wanted her to tie him Rakhi. Yesterday, he came to the house where my girlfriend lives with her three sisters, and all three sisters tied him Rakhi. She also told me beforehand that he was there, so after initially feeling a little uncomfortable, I accepted it.

What really hurt me happened afterward. She took a photo with him because, when I asked why, she said "mera maan tha" (I wanted to). He then posted their photo on his Instagram story, tagged her, and used a romantic song.

She also hasn't told him that she has a boyfriend. Her reason is that she doesn't tell people about our relationship because of "buri nazar" (evil eye). I don't really understand or agree with that reasoning, especially considering how this particular friendship has developed.

Another thing that hurt me is that she deleted Instagram notifications related to his follow request/acceptance and the mention because she knew seeing them would hurt me.

After I saw the story, I was very upset and told her about it. She then messaged him asking him to delete the photo and gave him her sister's number instead of her own. That calmed me down a little, but I'm still genuinely hurt because she knew this kind of situation has been a sensitive issue for me before.

I'm not saying my girlfriend has feelings for him, and I'm not accusing her of cheating. My concern is about trust, transparency, and boundaries. I don't want to control who she talks to or who her friends are. I just feel that some things have crossed a boundary for me, especially when she already knew how I felt about situations like this.

I'm emotionally very confused right now because I can't tell whether I'm being hurt by her actions or whether my own insecurity is making the situation harder than it needs to be.

I'd appreciate honest opinions from people who have been in similar situations. What would you consider reasonable boundaries here, and how would you handle this?