We live in a world of communication - everyone gets information about everyone else. There is universal comparison and you don't just compare yourself with the people next door, you compare yourself to people all over the world and with what is being presented as the decent, proper and dignified life. It's the crime of humiliation.
Partnerships are increasingly seen through the prism of promises and expectations, and as a kind of product for consumers: satisfaction on the spot, and if not fully satisfied, return the product to the shop or replace it with a new and improved one! You don't, after all, stick to your car, or computer, or iPod, when better ones appear.