Many would attribute the dramatic differences between a relationship's life span in contemporary times to that of our erstwhile companions to societal changes. I would however like to entertain the possibility of it being affected by the life span of our actual lives. Am I being clear?
You ever meet someone on a trip or have a steamy summer relationship all that more steamy because of the fact that both parties were aware that it would soon end. I mean if you meet someone some summer and realize you will inevitably soon part, what's the use in over analyzing incompatibilities? You're able to optimize enjoyment partly because you do not have to factor in your long term projected compatibility.
What if our life span was an average age of 253? Do you think monogamy would be so common. Forget monogamy but the idea of a life partner? I don't know, I'd like to think so. I'd like to think that the reason that some of us are able to have life partners now isn't solely because death is close enough to make it work.