How do you deal with an ex in your friend group?

I'll call him C.

We "dated" for a little while, but I ended things because I realized we just weren't a good match. Looking back, there were a few things that bothered me, like him interrupting people a lot, always needing to be right, and making conversations about himself. Nothing terrible happened, but I knew behaviors weren't very healthy, so I broke it off.

The problem is that we're still in the same friend group, so I see him all the time. He's friendly enough now, but he still has a lot of the same habits, and because of our history I get annoyed way faster than I probably would with anyone else.

My friends aren't exactly his biggest fans either, but I don't want us all just complaining about him behind his back. I usually try to ignore him or keep some distance, but it's hard when he keeps trying to get a reaction out of people or inserts himself into conversations.

I don't want to be rude or start drama, and I don't want to hold a grudge forever. Has anyone else had to stay in the same friend group as an ex? How did you handle it?