...presumes that your destiny is tied to another person. I suspect your current (healthy) attitude towards marriage is at least partially shaped by your current (healthy) attitude towards destiny: you don't have firm plans and goals so the idea of coordinating your plans and goals with another human being complicates things rather than simplifying them.
That's definitely part of it. I also grew up in a household which was persistently frayed and oft on the edge of divorce, grew up with friends who had parents going through divorce, and am currently friends with at least one person going through a divorce. The close proximity to the separation of tied destinies, I think, has also contributed to a mindset that doesn't view it as a leaning-towards-permanent, binding of two people into one, but as a more structured but just as apt to fall apart relationship.
I wonder when that graph will level out.