when does the healing happen

It's been over a year since the worst breakup of my life and, while i definitely feel better than i did then, the grieving has been extremely nonlinear. We still live in the same city, and ive been at the same bar as him twice this month, which reopened some wounds and sent me about 100 steps back when I thought I was finally letting go. He was cheating throughout half of our long-term relationship, was cowardly and selfish and didn't respect me enough to end things when he stopped loving me, and yet I still can't seem to get through a single day without thinking of him. I dreamed about him last night and woke up feeling like it all happened yesterday. It's like ptsd, but you can't say that to anyone because it sounds ridiculous if they've never experienced it and because "it's been a long time" and because I "should be over it by now." I want to be over it so badly. I want to hate his guts the way everyone says I should and the way I pretend to. But I can't seem to get there. I have a tenderness for him that's so difficult to override because I'd never felt so deeply seen or understood by anyone before or since. I have friends and get out a lot and try so hard to build myself up, but he just keeps coming back and poisoning everything. I know sometimes there's just a heartbreak you never get over, but I thought my feelings would at least turn to rage or disgust at some point to make it a bit easier. He let me go like nothing. How do you deal with loving someone who betrayed you and gets to just go about their life like normal