Most Helpful Guy
It isn't "wrong" but it is frequently a bad idea depending on how things ended. When you have that much emotional history when another person and things go poorly there is almost always complications afterwords. One person could still have romantic interest in the other and then be stuck in the infamous friendzone. Or there could just be a lot of hatred and resentment that never got out in the open.
I have only ever been able to stay friends with one ex but she is one of the best friends I have.
Most Helpful Girl
It's not 'wrong', most people just assume it's because you're taking a break and will get back together. Plus future partners may find them competition and it could course drama.