my girlfriend 18F is highly obsessed with her celebrity crush

So i am 18M and i am dating this girl for past 3 months now and have started developing a sense of insecurity due to her celeb crush.

She is so obsessed over her celebrity crush that she literally sticks pictures of him on her phone case and even had him on her birthday cake. She is so idk deeply in love with him that she even puts stories of his every instagram posts. She also gets defensive and angry even if i mildly joke about him too. THE thing which instantly turns me off is that she calls him her husband and me her boyfriend which idk makes me fell insecure.

I am deeply in love with her but i think as soon as she finds her celeb crush in someone (by that i mean of same personality or face card) she might break up with me in an instant.

So what should be my next move?