From Sugar. Probably and possibly the most accurate thing I have ever read on the subject:
“Leaving a relationship because you want to doesn’t exempt you from your obligation to be a decent human being. You can leave and still be a compassionate friend to your partner.
“Leaving because you want to doesn’t mean you pack your bags the moment there’s strife or struggle or uncertainty.
“It means that if you yearn to be free of a particular relationship and you feel that yearning lodged within you more firmly than any of the other competing and contrary yearnings are lodged, your desire to leave is not only valid, but probably the right thing to do.
“Even if someone you love is hurt by that.”