Why can't I get over him? I just want to stop hurting.

We've been apart longer than we were together now. I've done everything you're supposed to do when your heart is broken: I've spent time with friends, updated my beauty routine, gone on adventures, told myself that I'm focusing on school and myself right now, and so much more. But no matter what, I always think about him. I imagine how romantic it would be if we got back together, and then I remember that that will never happen and I feel so pathetic. I miss him so much. Thinking about him doing all the things we used to do with a new girl, after he's forgotten about me and moved on, still makes me feel sick with dread. I'm so tired of this.