Please help

I've Been a bad person to my girlfriend that has never did anything wrong to me(no I never cheated on her) I love her so much but she's giving up on me she's unhappy with me but I've been doing things differently but it's not working and I don't know what to do bc her being happy means so much to me but I don't want to let go. I came into this relationship looking for her to hurt me in someway bc of people in my pasted but she never did all she did was love and care for me but I want to make her happy again I just don't know what to do.