I don't know if I can help you, but I can tell you my story
She left me for someone else. She didn't want to bother with me any more, after 3 years and 4 months. At the time she was the only person I could connect with, we shared everything in our lives to each other, I've never been able to have this kind of connection with anyone else, I was all alone. At the end I did not blame her, because I was wrecked with depression and social anxiety and it was very taxing on her.
I cried everyday for 2 weeks. I had random panic attacks. I lost weight because I could not eat anything at all. I had a horrible constant headache. I was completely depleted of any will or hope. I tried to commit suicide several times, failed and only left with a horrible pain in my head from the rope strangling. All this with horrible, lonely all around torture inside me. After a while I was numb inside, the emotional detachment after a stressing trauma, do you get that too? It helped a bit to just think about things without having the pain. I even convinced myself for a short while the person I love is dead, and she's just some hollow shell of her that doesn't deserve me, surprisingly enough it did help to just cherish the good memories in blissful ignorance for a bit, but it's not the best thing you can do.
But you know what I did to try to cope? I had some friends in the internet, I'd just tell them to talk to me, tell me stories or talk about anything they want to just try to distract me from the pain. I started working out more, running and weights. I took better care of myself, independently, not wanting to ask help from anyone else unless absolutely necessary. I tried to beat my depression and anxiety by myself, it's a work in progress but I am doing a lot better than before. I took driving lessons, it's good fun, she did always tell me to take driving but I always said it was pointless before. I volunteered at a charity book shop, they're all nice people and the work makes me feel productive and good. I bought a keyboard to just play for fun and perhaps get good at it someday. I got back into education with a Psychology course with the OU, part time education but still, it all made me feel better about myself.
I still think about her everyday, not as in all my thoughts are centred around her. She's just there in the back of my mind a lot, not long ago would have been our 4th anniversary. I've still not met anyone as remarkable as she was to me, but I feel like maybe one day the new better me may finally and happily win someone of such greatness again. At the end of the day, I don't feel so bad looking back at it, I cherish the good times we had, and I want to be more great for myself and for my future partner.
Time may not heal you completely, I still don't feel like it has for me, but I can confidently tell you that it will definitely get better.
Sorry if it's all a mess, I just typed as I was thinking, I hope it provided some form of comfort.