Depends on the variables. If you have children together? You will need to have some sort of healthy communication for instance, being friends for the kids. I’ve seen a few of my friends who are amicable after breaking up. It also depends on the personalities, maturity, why they broke up. I do believe it’s possible. The relationship evolves. Me and my wife are friends with a few of our ex’s. Not to the point you go out for a coffee but you remember the others birthday, you can have a conversation if the need arises. A perfect example is if one of my ex’s was due to visit London with their husband and kids, asking me for pointers of where to stay. I would be more than happy to help. A lot of it comes from ego and insecurity. I generally have no qualms with my wife speaking to an ex and being friends with them. Age counts for a lot to as generally, as we age, we should mature and be better. In my 20s I handled situations and would have given a different answer to this. I would have said no for instance.