I think I genuinely feel that the most enlightening relationship experience I've had is being single after having all of my prior adult live in relationships
it gives one a look from a different angle when one sees couples together - there's a different viewpoint that shows -
one notices who walks in front, who hold their arm around whom, if they hold hands or not and one observes the calls for reassurance, sometimes a constant stream, sometimes, rarely.
It must be some sort of power in the position of observer, because you see something and you think 'yeah, I've done that' - or 'yeah, I know what she's doing there'