I mentioned it hypothetically to my mom about a year ago, as a "this is what some people do, I think it's fine if it works for them" and she came right out with "that's unethical." Then I explained that it's not unethical if everyone knows and consents. Then I mentioned that my husband and I were like that too. She said she didn't want to hear it, didn't want to know if either of us started "doing it" and that was to be the end of it.
This Christmas, there was that Dr. Phil show about polygamy. It was religious polygamy, not at all what we do, but it opened the door for another dialogue. This time, she was much less closed-minded. I mentioned again that my husband and I shared a similar belief about non-monogamy, and this time she was more accepting. She still stuck to her guns that she could never do it, that it must create a lot of jealousy, the usual arguments against it... but she let go of "I don't want to hear it!"
At both times, I was not currently in any other relationships. And sometimes, when I talk to my mom about people I've gone on dates with, I call them my friends... because at this stage, we've only gone on a couple dates, so it's not like they actually are my "partner" or "boyfriend/girlfriend" yet... And really, when I was single and dating, I never referred to anyone as "this guy I went on a date with" ... I called them my friends too.
But if any of those dates develop into something more serious, I intend to tell both my parents.
I've never told any of it to my dad. I have a really close relationship with my mom and we talk almost every day. I really only talk to my dad on birthdays and holidays, with a couple annual visits. But he's always been really open minded. I never told him I was non-hetero either, but when my mom told him, he said to her "Yeah, I figured that out years ago" so yeah... hard to surprise him! I also don't think my step-mom would be bothered by it. She's open-minded too, and very much "your business is your business, not my place to tell you what to do"...
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker