This is a lesson I was taught years and years ago by a family counselor. Today I can recognize when I am "sitting in shit that is warm and comfortable, but it's still SHIT" and get out a heck of a lot faster than I used to. I'm working on not getting in it at all. :)
This is true of all relationships, with our friends, family members, children and spouses. Always look for the good. The bad will be there if that's what you focus on but if everyone tried to see the good in each other, the world would be a happier place!