Is It Okay To Be Friends With An Ex?

Now I've written before and said I don't think that going back to an ex is a good idea as you all obviously broke up for a reason. But today, I have a different issue to discuss when it comes to exes, should you continue talking with them/ being friends with them once you've broken up? Okay, so here's my take on this, once you all have broken up, it's, in most cases, in the best interest of both parties involved that you go your separate ways and cut all communication. The reason I'd suggest no communication would be mostly that emotions will be confused. Not only will the emotions of the two parties involved be confused, but if one or both of you decide to move on, I'm pretty sure this will cause confusion with your new partner(s). You must remember that you have history with this person and what does it say about your relationship with them if you're unable to go on with your life without them in it? There are always exceptions to every rule, and maybe being friends with your ex works for you. Maybe you have to remain friends with your ex because you all have kids, whatever the case may be, all I'm saying is that in most cases it is best to leave your ex in the past... What are your thoughts on this?