[Eternal]

It's situations like these that show you who your true friends are. I agree with the above poster, this shows that this guy doesn't really respect you if he broke up with you because you wouldn't have sex with him. And your best friend doesn't really respect you if she had sex with your ex boyfriend without seeing if it was okay by you first.
For now, it's best to just wait this out. Try talking to your other friends about this and see if you can find someone you can confide in and talk to.
If you were too scared to go to his house alone, then he isn't someone you want to date. You want to feel safe and secure in a relationship, and if you are ever pressured to do anything you don't want to, then it's time to think about whether its worth it to stay or not.
You're still very young. I promise you will be able to make new friends, and you will have more boyfriends. I recommend joining a club or sport so that you can get to know other people with similar interests.