It's not like we break up and automatically become friends but it sure does take time. Long stories short, I'm friends with three of my four exes. My first love and I are pretty much still inseparable when we see eachother but that's far and between these days.
My other ex and I stay in touch through facebook regularly. We care lol. And my third ex and I spent two 1/2 years together that formed into a lifelong friendship I'm extremely grateful for now, though it obviously took months to reach a point where the relationship part fizzled.
My last ex can go fall, break a leg, have a car run over him, and die a slow painful death tbh. No apologies for dat one.

Btw I started young, like at 13, so don't think I'm a **** or anything lol