Rarely do ex's get back together unless they had some type of strong tie that draws them BOTH back.
A lot depends on why he is your ex
And you need to ask yourself even if you get back together is there really a chance it will work this time? Which goes back to WHY did you break up?
Probably not. We can't really tell you, we don't know you, we don't know your ex, we don't know why you broke up, or even who broke up with who. It's anyone's guess.