How stringing someone along prolongs their suffering.
Our Lives Consist of Pure Luck
The late moral philosopher Derek Parfit in his last book On What Matters talks a fair bit about luck. Luck isn’t just a constituent element of our lives, but it is also a consistent element of ethics.
What matters to us, fundamentally, is a matter of luck. The way we act in the world and the way the world reacts to how we act, are both matters of luck.
You can’t help but be the way you are, and the world can’t help but react the way it reacts. There is far less in the way of freedom in the world and in its ethical domain than traditional modes of thought would like to say there is.