Unfortunately, I haven't come out to my family yet and they think I'm just dating my primary partner. Wanted to share something, though about when my primary partner came out as poly to his mother.
Him: Hey, Mom, remember when (girlfriend's name) was dating (girlfriend's ex's name)?
His Mother: Yeah? Why?
Him: Well, I was kind of dating her too. And I kind of still am.
His Mother: But... you're dating (my name)?
Him: Yep. I'm dating both of them. And (my name) is dating (my other partner's name)! We're polyamorous.
His Mother: ...Oh, okay. Cool. (carries on with what she was talking about before)
(His mum's actually really cool though, this reaction wasn't surprising. Just amusing.)