It is false that relationships, once invented and defined, cannot be reinvented and redefined.
Take a look at this banal example:
You've been in a relationship with a guy or a girl for many years - your relationship is established already as you love each other. But one day, they cheat on you. Obviously, your relationship with them is going to change, usually for the worse, until, often, some day, there is no relationship at all anymore.
