Perfection is always an unrealistic expectation. The problem is NOT with "too much familiarity in relationships. The problem is there is not enough familarity BEFORE we decide to open up our hearts to someone. It takes awhile to truly get know someone. Unfortunatley most people "commit" to others before they know them.
The vast majority of people bend over backwards to "impress" someone new that they are attracted to. Most often during the "infatuation phase" they rarely use the word "no". This leads one to believe they have met someone just like themself/Soul-mate. After there is an "emotional investment" a person starts to feel they can "relax" or be their "authentic self" without the fear of losing their mate. It's not uncommon to hear someone say, "He/She is not the same person I fell in love with."
No one ever says, "I hope you know in a year, 5 years, or 10 years from now I won’t be doing all these nice things for you! You can forget about wild passionate sex. The only reason I went to the game, ballet, or shopping with you was because I thought you were hot! Once you’re mine I won’t feel the need to impress your ass!”
Finding true love would be a lot easier if everyone would simply be themself. In other words if you are not a "romantic" then don't pretend to be a "romantic". It's "bait & switch" that causes passion to diminish as people try to adapt to the reality of their relationships. Awhile back I wrote hub about the difference in how we treat "the new" versus the "tried & true."