This is a recipe for perhaps the most unhappy society imaginable. Without such outmoded ideas as 'commitment', and 'through thick and thin' relationships become subject to the immediate barometer of personal happiness. In practice this is anything but equitable, freeing and fulfilling. It results in people with perceived high 'value' flitting from relationship to relationship, often several at once. Invariably leaving relationships and abandoning partners when the ordinary vicissitudes of life arise - job loss, ill health, aging, deaths of parents etc.

Real intimacy requires investment. Relationship anarchy, any time I've seen it attested or practiced, faciliates the opposite. It's a fetishisation of alienation. What you're describing as 'pressure of expectations' can be understood very differently, as the expectation of reciprocity. In other words, being able to rely on people - whether as friends or lovers, when things get difficult. Without that, all we have is limerence and capriciousness.

I say all this as someone who's been in non-monogamous relationships of various kinds - from weeks to years. Without the possibility of commitment and the acknowledgement that all relationships are inherently hierarchical, we atomise individual needs and make real enduring connection and community impossible.