get over it
If she was real, she will not become an ex.
You do absolutely nothing about your ex boyfriend considering he has a new girlfriend. If he loved you he would break up with his girlfriend and since he has not then he wants to be with her and you need to accept that. Just because you have broken up with your boyfriend it doesn't mean you can just step back into your ex boyfriend's life.
When you date someone and have a relationship and your boyfriend or girlfriend breaks up with you then that makes them your ex boyfriend or ex girlfriend. 'Ex' means the relationship is over. When a couple gets married and then divorced it because 'ex husband' or 'ex wife' meaning there is either a separation and divorce and that person is no longer in your life.
maybe he wants you back.
Simple Answer: You don't.
if he thinks it's ok then sure.
Let him have a threesome with your sister (only if hot)
You guys are not meant to be
No, you should not email your ex girlfriend to try and get her back because she has another boyfriend. You had your chance to make the relationship work out with her and since you didn't then it time for both of you to go your separate ways.
If he has a girlfriend, don't go back. He will do the exact same thing to you, that he will have to do to his current girlfriend. Good Luck!
It means the ex boyfriend still likes the ex girlfriend.