Why does she wanna do this

I (18m) been with my girlfriend since 3 years now she just wants to leave me at every fight like I have build a alot for us and now she is planning to leave me for every stupid thing like I just can't understand I tried everything she wanted I never spoke to any other girls block the other girls in fact I literally started earning and still she does this how can she go thru this like why don't shee see all the things I'm willing to do I haven't been toxic I always spoke to her about things I always tried to do the right things even do I fail it happened with me on my last bday she broke up with me for a silly fight and then I didn't eat or even drink water for 4 days then after that i begged hee to get back and we did and I didn't do all these things cause I won't get anyone else I did it cause i wanted to build a real relationship with her nothing else that's why I just wanted to love her and only her no other woman now I'm gonna be a stupid ass bitch for no reason all I wanna do is love her