I hate this quote, mostly because it is referring to a relationship. If there is only one reason why you should stay, you need to leave. Do not settle for this person that makes you question your feelings towards them. Don't settle for the guy that gives you these other reason to not stay! Stop settling get the hell up and move the hell on
This reminds me of when Marmee from Little Women tells Jo, "Jo, you have so many extraordinary gifts; how can you expect to lead an ordinary life?"
If you did this, stopped fearing the worst, predicting some non-existant, bleak future where everything goes wrong, and resisted caving in to the pessimist you are, your family might be healing and becoming whole again. But it's all about the fear with you. Fear rules your mind, your heart and your decisions. And that's where we're different. I always visualize how great things will be if everything goes right, and how, even if something goes wrong, we'll fix it because we're together.