I mostly agree with you - included the "We're just better liars" part! :-D

I think humans are instinctively "hypergamous", i.e. they aspire at the best partner (having conquered the whole planet, it's obvious our species don't lack ambition and is seldom satisfied).

But since most of us are "average" and can't snatch the "best one", in time we tend to settle and choose someone close to what we want - but not "the one" we were dreaming about.

And since cognitive dissonance feels horrible, we tell ourselves (and others) he or she is exactly what we were looking for (after all, who does want to admit having settled?). Save for asking divorce, or having affairs with others, years later.

Yeah, "the love of my life" has expired. How nice ;-P

I think this is the hard truth. But people don't want to hear the truth. 99% of the time, they prefer the comforting lie instead. And so this goes on... :-)