When you realize he’s a liar the whole time, and that’s not the worst.
That he had chosen to give up because he’s not only a liar but he’s also a cowardly loser, who’s discovered he can’t keep up with you anymore and he will never be able to. That he could still imagine you would “look back with a smile” after what a disgusting person he’s been to you just shows how naïve and emotionally stunted he is. That his destiny is to flail his arms in a small pond thinking he’s a big fish, with cheap whores, fake friends in a superficial world.
To see someone’s true colors is sobering. It’s an awakening. There comes a moment when you finally see that it is the Universe’s way of clearing trash in your path. And it still hurts.
As Captain Holt says, never love anything. Never trust anyone. You should have trusted your gut feeling and all the red flags that had come up, but you were too blind to see because you actually believed in unconditional love. You thought he was real but he was just an empty shell that rang supremely hollow – the most inauthentic human you ever met, and unfortunately, loved.