The half life of a substance is the amount of time it takes to lose exactly half of its initial value.
In physics, it’s the time period unstable atoms require to lose energy by emitting radiation. In biology, it is associated with the time period required to eliminate exactly half of a substance from the body. In chemistry, it is defined as the time required to convert one half of the reactant(s) into the product(s).
In love, it is the amount of time it takes for lovers to feel half of what they once did.
And just like everything else- it wears out, runs out or finishes. But unlike everything else- once it’s gone, it’s like it was never there; then replaced by regret or hatred.