We experience it every day. Hate is part of our primal nature. A survival instinct, like hunger. Although we deny it. It's solid, it's there, and there's nothing we can do about it.
Love is shapeless, an abstract, and only present part of the time-like cold.
Allow me to explain. The hate was always there. In minute proportions perhaps, and after the cheating, or the distance, or the alcoholism, or the whatever, it just intensified. I think the words 'I love you' mean different things to different people. Think about it and answer honestly.