Thanks for sharing, rolypoly. Understandably there must be a lot for you to think about, and I'm grateful that so many smart and thoughful people are on here to participate in this discussion with you. I can especially understand how big the question of children and family you are grappling with is. It's a big, fundamental question, and I imagine it is huge and complex and grey and not black and white. I know that these questions are not straightforward for me.
I really like something LovingRadiance said, "So there are multiple ways for it to be worked out-but you really have to find the right fit for you (and the people you are with)." And I like what you said as well, "...dating someone who's married doesn't necessarily need to close the door on other possibilities."
Personally, I have learned that I can't even know what is actually possible, because everytime I think I have figured out what is, or is not, possible, reality exceeds what I previously thought was the upper limit of possible and proves me wrong. Heck, at one point I even thought that myself and RedPepper being happily polyamourous was impossible! The realization that I was *soooo* completely wrong in that particular belief, which I had held with such high confidence, was enough to demonstrate that really, I have no idea what is possible, and what isn't. The only way I'm finding out what is possible for myself personally, and what is possible within my family, is by trying it. The limit of possible seemingly keeps getting bigger. I can't speak for RP and Mono, but a year and a half ago, I never would have in a million years have imagined that we would be where we are today. It was beyond my imagination, beyond sense of possibility, and now it's reality.