This is an interesting question as I've been going through this for the past year.
I was actually ready to marry my girlfriend and it fizzled out. Unfortunately, it wasn't like either one did anything to force a break up, things just had run their natural course and there was no road left on that path for us and time to go separate ways. I still talk with her and consider myself her friend. I like to think I've moved on from her, but I haven't had any luck starting a new relationship, something I consider to be the final piece in really being able to move on, having someone else to occupy your heart. It hasn't been easy being her friend, but at the same time, I can't imagine totally cutting her out of my life either because of how much she meant to me and she's done me no wrong, just doesn't feel as I do. There have been a few moments where old habbits have kicked in with her which doesn't help matters, but I could easily do that myself. Thankfully, I don't see her in my day to day, so whoever she may be spending time with I don't have to know about because it tears me up inside to think of someone else being in the position I once was, can't imagine actually knowing someone was.
I guess what it boils down to are what the circumstances of the breakup were, how much the other person means to you, and whether or not you both can put your "relationship" ways behind you and interact with each other purely as friends.
Really, if their friendship is something you want, it's worth a try and worst case is you find it doesn't work and you move on, but if the situation is one that would allow you to try to be friends but you don't at least explore that, I think it might leave you with some regrets.
I was actually ready to marry my girlfriend and it fizzled out. Unfortunately, it wasn't like either one did anything to force a break up, things just had run their natural course and there was no road left on that path for us and time to go separate ways. I still talk with her and consider myself her friend. I like to think I've moved on from her, but I haven't had any luck starting a new relationship, something I consider to be the final piece in really being able to move on, having someone else to occupy your heart. It hasn't been easy being her friend, but at the same time, I can't imagine totally cutting her out of my life either because of how much she meant to me and she's done me no wrong, just doesn't feel as I do. There have been a few moments where old habbits have kicked in with her which doesn't help matters, but I could easily do that myself. Thankfully, I don't see her in my day to day, so whoever she may be spending time with I don't have to know about because it tears me up inside to think of someone else being in the position I once was, can't imagine actually knowing someone was.
I guess what it boils down to are what the circumstances of the breakup were, how much the other person means to you, and whether or not you both can put your "relationship" ways behind you and interact with each other purely as friends.
Really, if their friendship is something you want, it's worth a try and worst case is you find it doesn't work and you move on, but if the situation is one that would allow you to try to be friends but you don't at least explore that, I think it might leave you with some regrets.