I feel like there is a similar but opposite bias to survivorship in the reporting of relationships in general: you only hear about the bad ones.

My friends are all freaks and geeks, much like myself, but even in our group those that are in relationships at all have been in them long term and are at least seemingly happy with them. This seems like the usual case in the general population too - bad cases become gossip (or news if the people are famous), but most of the stable cases don't make a big deal about it.