Excellent post on the issue! Acceptance of non-monogamy is going to be the next push after LGBTQ+ issues get settled. I think the sexual aspect of it is the most talked about because it's so antithetical to the current structure, and of course because sex sells, but there is something that the ideas of it can extend to people who aren't interested in having multiple partners. Somehow along the way, your romantic partner became expected to become your best friend, your lover, your business partner, and your caretaker. It's frankly insane we expect all of this from one person. We cut out having deeply intimate relationships with non-sexual partners (and this is doubly bad for guys, thanks toxic masculinity!) and overload our romantic ones with all of our baggage. This probably has something to do with, as you mentioned, the change from focusing on an entire village as a unit to the nuclear family as a unit.

At the end of the day, we can only benefit from maintaining as many meaningful relationships, whether those are sexual or non-sexual, as we can. By doing so we have a broad base to draw on when we need support, and a diversity of experiences to help us enjoy everything life can offer.