A (slightly edited) comment I left in
Polyamory isn’t primarily about sex for me at all, but about multiple committed relationships with other adults that may or may not involve sex. I have two SOs who are not lovers and who are very unlikely to ever be lovers. One of those relationships has been stable for many years now (more than five, getting close to ten).
Every relationship is unique. Some include sex, some don’t. I don’t know that certain relationships “need” sex, but some of them definitely have a deeply sexual vein. My primary partner and I have continued to build relationships with some of our former partners that do not include sex, though those relationships were as lovers in the past—things aren’t the same, but they’re still family-of-choice. They are people we value highly, love, and would not want to lose. Sometimes, for a multitude of reasons, being lovers just doesn’t work with someone. It might be a “right now” or an “ever,” but that doesn’t change the fact that those people are very important to us.
I definitely see a difference in quality between friendships and SO/family-of-choice relationships whether they do or do not involve sex. I’ve had friends with whom I occasionally had sex, and I wasn’t as close to those people as I am with my family-of-choice (lovers and non-lovers).
We keep our relationships going just as we’d keep any relationships going—we make time to be together. We communicate. We don’t hold back. We call bullshit on each other, support each other through good times and bad, play together, work together.
I can definitely see living with these people, raising children together, staying together for many years. That is one of the key indicators, to me, that a relationship is much more than a friendship.