I want my girlfriend to cut off her fwb
How could she do that to you?
She told me humiliating me and talking about me behind my back
Controlling behavior can be incredibly detrimental to a relationship. You should both fully express your thoughts and feelings, but you need to do so respectfully.
I know what I'm doing. She loves me. We only do it when we're drunk. I know my girlfriend.
You two may love each other, but I believe you need to realize that she is being a little abusive to you. Relationships are supposed to be respectful, and her having a FWB and humiliating you doesn't sound like one, doesn't it? How about just trying to talk it out one last time, and if it doesn't work, to move on?