Blast From The Past: case of the Ex

Seems like there should be like a "street code" court for these types of things. How do you handle those ex's who are cool with your family, even after the break up? You know the one you met through a family member and way after the relationship has ended they still come around. Well it may not bother you as much if you don't still have feelings, as a matter of fact you might even get over it and pay them NO attention... But what about your "Next"? When I say "Next" I'm referring to the new boo who is after the Ex. How does that person handle this situation? It's got to be uncomfortable for them. My advice, tho every relationship is different, is to stay away from it. If everyone isn't comfortable and if you can't control whether or not the ex comes around, let you partner know. That way the two of you can decide if that's a function you'd want to go to.