It's time to let go, stop wallowing in your pain and self pity and forgive. Holding grudges on people is emotionally draining, and truthfully- you are so much better and above this now! Holding on to whatever it is that made you unhappy will not help you move on with the future. I know this is hard, and it sometimes feels impossible depending on your situation (I know I've utter the words "unforgivable" to someone). But the thing is that other person will have to live with what they did for the rest of their life- not you.
Forgiving them has nothing to do with them, and everything to do with YOU. "To forgive someone doesn't mean you trust them or want them back in your life. It means that you understand that all anyone does is the best they can do at the time, even if it seems to you that they could have done much (much) better. True forgiveness feels like your emotions are no longer charged when you think of them"
And you know the best reason to forgive? "Forgiveness opens up space for love to come in."
The best part about this lesson is it's helped my realized that I've forgiven someone in my past. I've moved on. He is no longer in my life, and when he tries to insert himself back in with an "I miss you text" it doesn't make an emotional dent in my day. This weekend I found myself sharing with friends I hadn't seen in a while about all the new great things I'm up to. His name wasn't mentioned once. It wasn't until my girlfriend asked about him that I realized I hadn't even told her about what he had dont last to hurt me. Not including him in my "life update" is what made me realize, he really isn't in my life any more, and although I thought what he did was unforgivable, the truth is I had forgotten it and him.