You're not a theist, so your explanation suffices.
I wouldn't say I anticipate the possibility of change with any type of worry or fear. I, too, subscribe to a fairly uncommon archetype of sexuality. I wouldn't be surprised if I had to change it, for perhaps my mind is not properly aligned with nature... and I'm missing out on something transcendent.
I'm not going to lie to you. I find heterosexual polyamory disturbing & offensive. Homosexual polyamory, not so: you can entertain all the same-gendered partners you want, but to entertain more than one opposite-gendered partner is what I cannot comprehend.
A world with homo & hetero monogamy, as well as homo polyamory, is the most "open" moral system of sexuality I am willing to accept. Hetero polyamory, especially those practicing sessions of group "activity", is where I draw the line.
Current law systems make it impossible for me to protest such behaviors the way I'd like to. Hopefully vigilantism makes a return in the next world. I'm waiting with bated breath... :beach:
Why is heterosexual polyamory so disturbing to you to the point of wishing to commit violence against those who practice it?