I'm friends with most of them. A couple I've lost contact with over the years, but mostly we're on FB/Christmas/birthday terms and a couple are good friends.
Mostly the reason we split up was because of life circumstances at the time, going in different directions. I've never been the sort to gave major raging arguments. I have met some lovely men over the years, and I'm happy they're still in my life, even though we have gone on to different relationships. I'm also still in contact with some of their siblings and parents, too, as well as new partners. It's normal for me - a former fiancee of my father's came to his funeral.
I would be wary of any new partner who wasn't in touch with any of his exes. (I'm 50s, so any potential partner is likely to have had previous relationships.) It would at least imply their approach to life is quite different from mine - i know plenty of people who do lose contact with everyone at the end of their relationships. If it comes over as a narrative of mad crazy exes, that's more of a red flag. I grew up in a small town - I wonder if that is part of it. It's difficult to lose contact entirely in smaller communities and so easier to be amicable about things- though you may need some healing time first.