How do you let something go

i find it really hard to trust but 3 years ago my trust was breached by my boyfriend. he says it wasn't cheating but he did say some things that ended up hurting me to an ex girlfriend/extremely close friend of his . i want to forgive him and let it go but after 3 years most of our problems in our relationship are due to this. if this had no of happened we would have been fine. i dont know what to do i dont want to leave him . but it still hurts me . i still cant believe he could even say the things he said to someone else "maybe someday we can be together" .. he says he spoke that way since they met when they were five and that they tired to have a relationship but it failed . he says he hasnt spoken to her ever again that i was more important and that he's sorry for what he did but he's so angry and upset if the topic comes up and i get yelled at . i know i suffer from depression. i try to fight it every day . i want to be myself again before the depression took hold of me. but it did the day i saw the msgs to her. i use to be confident and loved life. im not an ugly person or unhealthy and everyone else sees me happy for the most part and talented. but the depression kicks in and i remember what happened three years ago . and i break down. i just want to trust again and i dont know how to let go of the past . im just so mad he was able to do this .

why worrie about something he says years ago.you know.if he said that he might have been honest.but didn,t mean to hurt your feelings,are to you to find out.does he see her.are do you.just keep a open mind to let your relationship to grow.if not it will die.you have to key

You want to , but still unable to ... You want to live with him , but unable to do .. You may want to leave him , but unable to .. You may want to forgive him , but unable to.. You may want to forget him , but unable to... Simply because .. You are yet to completely live with you.. He is someway filling in the emptiness , the yearning you're looking for ... and for him to do it, you may want to let him go , but you're unable to , because you being complete is dependant on someone else. Which is not the way to live .