That's a great question, Wildflowers. And it's why I'm here.
For me personally, the goal is to be in any honest, loving, caring relationship that allows both partners total freedom to get their needs met in any healthy way by any appropriate person (whether sexual, emotional, intellectual, and so on). And that ALSO leads to parenthood and family.
It could be ANY type of relationship, yet so far both my mono and poly experiences I've had (and most of the ones I've seen) have not truly had this, because of either some shade of sexual/romantic possession rearing its head or an imbalance that develops over time. I'm not sure if I'm explaining this correctly, so happy to elaborate or try to clarify.
And I'm open to alternative suggestions.