Why do they keep talking about her to me?

Why does my ex-girlfriend family keep bringing this girl up in conversations whenever I see them? If I talk to the mother or father it’s always have you seen her or they try to tell me the things she’s doing which I don’t care about. The aunt who I see once a year maybe on my way to work ask me the same question of seeing her outside or inviting me to family functions knowing this is where she will be. I mean can’t these people see that for 3 years I haven’t said anything or seen this girl.