A Girl Named Lionel and Relationship Rot

I have suffered with insomnia for a number of decades and reading in the middle of the night is how  I usually get through it.  I average a book a week chosen these days from a reading list I've compiled and picked up at one of the many libraries run by the Ottawa Public Library Board.  I enjoyed reading this book very much.  Lionel Shriver is best known for her Orange Prize winning We Need to Talk About Kevin which has also made it to the big screen.  So Much For That was a finalist for the National Book Award and deservedly so.  It is mentioned as somewhat a criticism of the medical system but I loved the characters and empathized with the main couple who we get to know very well.  Their struggle as a couple is very representative of what happens to long lasting relationships.
Again I ask myself why are relationships so difficult?  What happens between that wonderful, heady beginning of a relationship when everything that person says, does, thinks is important to you and delightful...to the time when you can no longer look at them fully and have to continually squelch  sarcastic remarks to everything they say.  Okay, I know I'm overstating it but you know what I mean.  A friend of mine said, when I put this question to her, oh it's hard because life happens and there's the dog to be fed and the garbage to put out and the kids to bed and jobs to get to day in and day out...
And maybe that is all the answer there is. 
Meanwhile I am working away on my newest project, crochet this time; a granny square afghan photos of which I will share tomorrow.
And by the way I hope you have things that get you through, too.