Would writing a farewell letter to my ex-boyfriend help me stop grieving so much?

Almost eleven months ago I broke up with my boyfriend to get to know another guy. We were in a long distance relationship...he was ready to propose to me (keep in mind i'm only 20). After we broke up I was d and aulted. He found another girl two weeks later with the same name and hair color. They are still together and I haven't talked to him since January. I have seen a therapist and written him several goodbye letters, but never have I given them to him. I know we'll never be together again. The thought of living this life without him seems terrible. Time has not seemed to heal me much, especially since it seems I dream about him often. I'm wondering if writing him a letter would just make me look like a fool? I never got closure...it really feels like a death. I want to tell write to him anonymously, although I'm positive he'd know it was me, and tell him all the things that have happened to me and how I feel. Would writing him a letter help me to stop grieving so much?