I'm thinking of how my ex wouldn't stop cheating on me. Now we're best friends but neither of us have been able to see anyone else.
Is she also having trouble finding someone else?
Yes.
It is hard to end a relationship but it does you no good to be around the person after the relationship ends. You will keep causing each other pain.
Ok, I'm going to get her to find someone.
It's nice of you to do that for her. There's a lot of pain in your relationship, and that might be why you two can't find anyone else. Help her move on by finding her someone.