I'm really sorry this is happennig to you. To be honest, i'm in a similar situation right now. BUT i can reassure you that you can love again. Please read carefully, if she doesn't share these feelings, she's missing a great man, because after everything she has done to you, you still love her.
I'm not gonna lie to you, letting her go won't be anything easy, but do it for the sake of yourslef. Also, it will take time, so please make your best effort each day. Look for people you can trust and could help you. Get ALL of this out of your system and remember that there's someone special for you out there. I might know what you're thinking right now: "But i'd wish SHE was the one", I'd also like to tell you that, but it seems she won't be, and i'm REALLY sorry to tel you this, but try to move on man, it's been a year already.
I'm glad you're looking for help, and remember, we're here not only looking for help, but also you can help yourself by helping others.
Be patient, strong and also feed your willpower. You're a strong and a very valuable person, and believe me, YOU'RE happy, WE'RE all happy, but sometimes we forget it.
So, again, thanks for looking for help, it's much worse if you keep it to yourself.
God loves you buddy, best of wishes, merry christmas and remember that you're not alone