Letting go is the hardest part.
We give people too much power. Hazardous amount of power to influence what we are. The way they behave while you talk to them. Or the way they can ignore our presence like we weren’t alive till the previous day or we won’t be any longer is always an amusement. They can make you feel like shit on any given day and any given moment. They can strip you of your self esteem. They don’t consider you alive as long as they don’t need you. Your happiness doesn’t matter to them. Your world that’s falling apart is the least of their concern. They are cold, and blunt, venomous and everything .
But you know you just can’t let them go. Because deep down, you know you love her/him. You hate that fact. But you just can’t stop loving. And that’s bothering the shit out of you. 
That’s the way they are maybe. Like whisky, which is not of any taste to the tongue, they may not be any good till you get them. Neither might they ever. 
Never give up on them if they are worth it.