charlie brown – the tactic for explaining anything to goyim is to just keep the details out of it. I simply say, “It is the custom of my family that the men do not wear rings. Only the women do”. Once or twice I had a raised eyebrow at that response and then I gently added that my family’s customs pre-date the double ring ceremony.
No one has ever asked me “why” the custom is that way. They’re not interested in why. I suppose that if goyim wanted to know the “why” behind customs they would have a difficult time living with their own religion.
I once had to explain it to a frei person, so I mentioned the reason with the egel. But only because he wouldn’t let me get away with less (he was not asking for personal enlightenment, or I would have been glad to talk).