How long should i wait to meet new people?

How long should I wait tell I meet new people or should start dating. I have been with my ex boyfriend for almost 3 years how long should it be till I meet someone new and have feelings for. I know he is moving on because he wants to be with this girl...

that is 4 years older than him he is only 18 and she is 22 years old and I don't know why he wants to be with an older girl she is going to get all old fast and he would want to look at girls that are younger and not older but you never know it could be a trend because a lot of celeberties have an older girlfriend. but I need to find someone to keep my mind off of him but I still have a lot of feelings for him. we were even thinking about getting married. I hope I will find some one but how long should it be till I start flrting with some one else. should I wait for two or three months or should I just start. All I don't want is if I move on and I find someone that I like maybe he would want me back some how I think there is still hope for me and him. so help me I need some advice thanks

Think of it this way...

Rebound relationships RARELY succeed. So, if HE has moved on, then YOU are allowed to move on. There's no waiting period required. In the end, neither of your new relationships will work out anyway.

So just use it as a way to get over him, but don't do anything stupid...