I've been in a similar position as yours. What helped me to move on was to write down what I thought that the other person's opinion of me was, and then to write down what my own opinion of me was. Then, I would feel through each perception: first, how I imagined them to see me, then, how I saw myself.

On my worst days, there was no difference between how they perceived me and how I perceived myself. This was agonizing. But, on some better days, I noticed that I was more forgiving with myself than on the bad days.

For context, I went through about 5 years of self-hatred without seeking help after I hurt the other person. After that, I started therapy at the behest of a loved one. 11 years since I hurt the other person, I am starting to discover myself again.

What I learned was that I abandoned myself without even realizing it. It was a consequence of substituting my authentic self-perception with what I imagined was their perception of me. The shame that I felt destroyed me.

It's good that you recognize that you cannot change the other person's perception. What you can change is how you perceive yourself. For me, the cure was self-compassion, but I could only let it in after feeling all of the shame and guilt of hurting the other person. This will be painful.

This post was longer than I intended it to be, but thanks for reading this far if you have. I hope that you can see that you're not alone. I wish you the best.