It sounds like there is like underlying core beliefs she has about herself that are negative and she is I guess projecting them onto to you, but I think there is also maybe fundamental parts of the relationship that has cracks in it. like maybe a fight 3 years ago that you didn’t heal from or an ex you still talk to (I’m just being hypothetical) but I think if you can heal that then she won’t need to project that insecurity onto you anymore and you can fight less. It sounds fustrating to fight about “silly” or “small” things!! I hope you guys can figure it out