Okay so here's the story. I dated this guy for 6 months and we broke up and I still really like him. I told my best friend about it and she told me that she liked him too. A couple days later she asks him out and he says yes! I was so crushed! I couldn't believe that my best friend asked out the guy that I really liked! Even though that worst part of it is that she knew that I liked him still. What do I do? I need as much help as I can get.

Forget that best friend, she's not your best friend.. maybe she was but she changed now for the guy.. so she's not worthy of being called your 'best friend' anymore. The guy said yes to her, he never loved you, he just dated you, because if he loved you he'd never had said yes to her, he would've come back to you.. he'll do the same with your so called best friend. He'll breakup with her when he's bored and then say yes to any other girl. Never date anyone who you don't know and understand. Most of the guys just want sex that's why they get into a relationship, your work is to act smart and not get fooled and not let him use you. Just get over them both, your friend will return back one day crying and saying sorry, because that guy will dump her one day, sooner or later, I guarantee this. Just get over them now. And even if the guy comes back to you, don't say yes. Wait for the one who's made for you.

How old are you? I think you leave them alone to enjoy there time together and get more friends to enjoy yourself with. I see that's what you are doing any way, so looks as if you have things under control.

https://www.askmehelpdesk.com/dating/does-he-like-me-back-637211.html

I'd like to start by telling you that you shouldn't pin all of the blame on to your friend, your ex is kind of mean to start dating your best friend when he doesn't know whether it's okay with you.
Your best friend should have asked you first, and then acted on whatever you said. To gain some perspective she probably justified it by thinking that you'd already been out with him and it didn't work out, and therefore she thought it was okay to date him... however it is not okay for her to date him WITHOUT ASKING YOU FIRST. I think you should talk to her calmly, no massive arguments - take the moral high ground :) Ask her why she's done what she has! Don't be friends with her again though, you can't trust her.
I think you should just forget about the pair of them and leave them to it, you're only going to get hurt by being involved with them, pursue a different guy and best friend, I'm pretty sure you'll find much more trust-worthy ones :) <3 xxx