Being in a wrong relationship is always better than being in the wrong marriage.
In as much as I understand where you are coming from with this, I honestly think that non is bette. A relationship is even worse if you ask me. Here is why I said so especially with a narcissist. This is because while in a relationship, they might manipulate and expose you to some behaviors that would so mar your life that if care is not taken when that relationship is no more will make a person see life very differently and wicked and that mindset alone could spoil so many things for a person for the rest of there lives. Making it even difficult to enter other relationships and giving other people the chance to help out.
The best thing is to run like you rightly pointed.
Thank you for taking your time to comment on this @gloglo. I guess I didn't express myself rightly here.
I didn't mean that the person should continue in such relationship. But we can't always know some people until we are into a relationship with them. It's better we know who they are during the relationship that to marry them beforehand find out.