How you guys deal with your fiance having a Male BF?

FFS, this is not mamakutty/Male Bestie rant. I am genuinely trying to understand how this plays out. I am grateful for my best friends (irrespective of the gender) as they have helped me in lot of situations and I share great memories with them. I understand that the same goes for my fiance. But I want to press upon the fact that the BFs shouldn't interfere in our personal space and I expect my fiance to prioritise myself over her best friends. Is this not a fair ask? In one of the instances, I came to know that my fiance shared an important event in her life to her male BF before me. That sucked. Even small things like prioritising his insta messages. Like, she goes out with him for movies a lot. These days, I feel like I should also join them. But that would make the society to blame me as someone who's suspicious of her. I tried communicating this to her in the most humblest way, she got so defensive and used the typical "You are Possesive & toxic" card on me. How do you guys deal with this situation? I am here to see my opinion challenged and change. Give your honest comment.