There are some interesting input here, however, pointing out "negativity" because of some geezers' comments is rather strange. There are many "positive" people too. I find people way too positive sometimes.
Our experiences are different. Some goes through hell, some are born lucky. Some are lucky in business, some aren't. Some find soulmates, some don't. Just because someone has good experiences or has more willpower, it doesn't mean others have the same.
As for love needs to be nurtured, it may work for some, it may not work for others. Can't put everybody in the same hat.
Some like to get into the routine of belonging to each other no matter what, some may try hard but feelings may deplete. For some women nothing is good enough, for some the bare minimum will suffice.
I like your idea of "you and me against the world."
Been with my missus for 13 years, and I can agree that this philosophy works, however, sometimes, things change and become irreversible.