See, here's the thing:
Once you've been involved with someone romantically, can you ever truly be friends with them again? I like to think that you can; it's what I've always believed. It just makes sense to me that once you've cared for someone, then it should be fairly easy to keep caring for them, at least enough to create some sort of friendship.
But maybe that's a bit naive and idealistic on my part.
Maybe once you've been in love with someone, you've experienced such a deep attachment, that it would be hard to ever really let go of that. So, you would constantly be having thoughts and opinions based on the bond that you had before. Or maybe the only way to transform that habit is through the process of practicing a new habit, of indeed practicing a satisfying friendship.
I mean, that must be how successfully divorced couples do it. The ones who become friends and partners must practice a new habit, while the ones who cling to the old relationship mire in bitterness and acrimony.