Something like this does happen, even the people in it, they knows something is wrong somewhere, but love for the person can't let them take a step forward, it's like a kind of game, where the person do not win, unless the opponent let him/her to see their card.
Telling the person to leave the relationship, we find out that there is no need, as he/she still loves, resolution lies when the other person's change, and love back fully.