I'm going to threaten to leave my bf because he lied to me about walking another girl home
Why would he lie about walking another girl home?
Because he knows that I'm not very fond about that person he walked home with
You shouldn't jump to conclusions. Maybe he was just being nice and there was nothing behind those actions.
He put me in danger because he knew I'll hate the entire thing. That's why I'm going to tell all of our other friends and make him feel bad about it. He deserves this trouble.
It sounds unreasonable to threaten to tell his friends in order to guilt trip him. Talk to him instead about this issue like adults in a relationship. Involving others won't help anyone.