Hi Julie - I'm sorry you're experiencing this.
A few thoughts that I'm working on myself: try to connect with new people and activities outside of your shared circle of contacts. I have so many close ties with my former spouse between our family and friends, and it made the desire for him to "come around" or "realize he was so wrong" even higher because I envisioned how we could all spend time together again and pick up right where we left off. Unfortunately, it just doesn't work that smoothly.
I picked up tennis lessons at the city park, joined some other social groups (these can be free or paid activities - meetup.com is great for things like walking groups, yoga, coffee hour, book club, whatever you're into!), engaged more with my coworkers, etc. It didn't all happen overnight and making new friends as an adult feels HARD... but I've been surprised how kind people are, and how many other people are also looking for connection. And the more time I spend with these people who know nothing about my ex, our shared memories, etc. the more fulfilled I feel in my current situation.
Would I like him to be a part of those things? Yes, I sure would. But he's not, and these new connections and hobbies are showing me there's life and joy on the other side.
Wishing you all the best.