b) Both people in the failed relationship don't want to be there
c) One or both of the relation-ers want to decapitate the other member of the relationship.
Thus, it becomes a relationshit.
Often occurs when a significant other steals/lies/cheats/becomes clingier than plastic wrap or you JUST START TO HATE THEM.
Rebecca: I hate the way he breathes. I hate the way he eats. I hate the sound he makes when he watches football. I want to hit him with a car the majority of the time i see him.
Heather: You got yourself a relationshit.