It is always okay to quit a relationship, job or situation that is hurtful, stifling or simply not in your best interests. I think relationships are often the hardest to quit even if it is abusive or dysfunctional, because it takes courage and a sense of self to be able to realize that a relationship is not working for you in the safest of situations. So when one is feeling dejected and full of self-doubt, it is almost impossible and that is when it is more than okay to quit.
You can say the same for certain jobs where you are poorly paid, living from paycheck to paycheck, suffering under the yolk of a boss from hell, those are the times when you need to get quit and run for the hills.
I think that this question really refers to a person’s sense of self-respect, personal boundaries and an overall sense of self.
A very important question worthy of introspection for success in one’s life.
laurieanichols 
Thank you for sharing this post. It is okay to quit a relationship when it is hurtful especially a friendship with a toxic ‘friend’ or frenemy. I too was in a hurtful friendship with a frenemy (a flatmate from hell actually) who always got the pleasure of bullying, backstabbing and belittling me with her Dr Jekyll and Mr Hyde personality. Endured with her for one and a half years until I finally have had enough and realised it was doing her no good as a person and leaving me hurt as a victim. Long story short, she has been out of my life for six years and I pray to God that I won’t be meeting her anymore anytime soon as I last heard that she still bullies others and leave hurt people in her wake.
I’m glad that you were able to be strong enough and get out. You did the best thing for yourself.
That’s wonderful.