what do you do when the honeymoon phase is over?

"It's over. It's so over." - Meredith Grey

We all go through honeymoon phases, with people, places, things. We are blissfully and ignorantly happy and living in the moment, every moment, not thinking of the big, scary future. And then, eventually, the shine begins to wear off and aspects that were initially enchanting become tedious and frustrating. What was once so easy and carefree slowly starts seeming like work, and you notice things you never noticed before, like chipping paint or funny smells. So what do you do when when the honeymoon is over? There was something that attracted your attention in the first place, but how do you hold onto that when you are overwhelmed with evidence to the contrary? What if you don't want to hold onto the warm fuzzies at all...but you can't let them go? Do you cut and run or stay and fight?