I'm going to keep my fwb from talking to his friend all night
Is there an issue between you two?
Yeah, he's a real douchebag, I don't want that guy anywhere near my girl.
Since you and your fwb are not officially together, they have a right to be friends with whoever they want. If you want more of a say, then maybe you could consider a relationship with them.
I'm not going to do that. I'll make sure I'm the only one that gets to decide who she can be friends with. Fuck no.
That isn't very fair to her in the situation. You shouldn't tell her who she can see or what she can do. If you are having issues with you, you can always sit down and talk about it.