Let me start off by saying that this life is short. It's too short to hold grudges and it's too short to continue letting the weight of a heartbreak tear you down.
I know you loved them, but it's time to love yourself more.
You may have never even gotten an apology from them and you probably think I am crazy for telling you that it's okay to forgive them; but it is.
You see, when you forgive a person who wasn't even sorry... That's strength.
I completely disagree with saying "forgive and forget." Forgiving someone does not mean that you will forget what they did. Forgiving someone is only giving you a sense of peace.
That doesn't mean that you're surrendering and you're letting them win, because if anything, you won. By forgiving them, you have helped yourself let go. Let go of this weight that they put on your shoulders. Let go of the pain they left you with. Let go of having the hope that they will apologize someday. You win because now you have the satisfaction of accepting reality, and accepting that you deserve so much better than that.
Forgiving them does not excuse their behavior nor what they did to you, but it does prevent their behavior from completely destroying you.
At some point you will have to move on with your life because in all reality, you can't start the next chapter of your life if you keep rereading the last one.
So don't forget, just forgive.