my bestfriend is jealous of me having other friends and i don't like having someone possessive of me

hi i need help my online bsf is jealous at me interacting with my mutuals on twitter. I don't blame her, we already communicate this through but we haven't found the situation yet. i wanna stay with her, but the problem is, she's always jealous of my mutuals despite my constant reassurance that i still love her more and like her better.

she said no matter what, she feels like she's getting replaced and people always prefer other people more than her. she can't help it, it's just what she feels and she can't stop it no matter what, that's why she's avoidant, to protect herself but recently we got really close and became bestfriends. but then i interact with other people more, and she became distant but we communicate about it after, it's just that i still talk with other people and she could see it but i also dislike other people being possesive to me, but i still wanna keep her as my bestfriend. that's what got us in constant fight right now, i wanna stay with her and fix it with her, but I don't know how to. i need help fixing her beside telling her to constantly reassure herself cuz she already tried that and didn't work.

i want her to feel safe with me despite me talking to other people. i need help finding middle ground for us and fixing herself as her bestfriend too. if it helps, her mbti is enfj and type 2, we're still 16.