Why can't we just get along?

I've seen it done, so I know it's possible, but I have never been able to achieve it: Remain friends with the former significant other. I generally like the guys I have dated, that's why I dated them in the first place. Often what I miss when they are gone, is a sense of humor or perspective or the ability to say something outrageous without fear of reprisals. I am completely at peace with the fact that he has moved on, and I know the boundaries--but some how it gets complicated by something I don't understand and that's the end of that.

I don't expect that this is one of those all-the-time friendships, he's got a life, I've got a life, but can't we chat once in awhile. Except that the last time I tried it, with the last boyfriend (and I do mean LAST boyfriend), everything went well until, I guess he got tired of me as a friend, the way he was tired of me as his girlfriend.

Maybe, it's not possible to remain friends with the former significant other. Maybe those people who claim friendship are doing something else. I don't know, I just know that there are one or two with whom I wish I had remained friends instead of becoming something other.