Tigsy that sort of stuff can be so difficult to hear, and you get the nostalgia and recherche des temps perdu vibe going and it's all awful and difficult. I still find it horribly difficult to even hear the name of where we used to live, it gives me such a lurch in my stomach, and it's more because of the good memories all gone wrong than the bad stuff. It's mourning for what you thought you had and the life you thought you were going to get.
BUT the children have some lovely memories, they are all good friends despite your ex's machinations, you have the utterly wonderful Mr ExA and life isn't bad at all.
Stick a DVD on and get them off the subject . . . ((Hugs))