He asks: Why can’t I be friends with my ex?
HA! That skanky, no good, bottom feeder with the tacky hair, make up and clothes?? Ok this may not be an accurate depiction but I can guarantee that’s very similar to how the new woman will think about her. Especially is she is single, or still being a “hoe” (cause we’re calling her that too) you have all you need in your new girl. Well you’re suppose to anyways. When its over- its over (for a reason). The notion of you still being friends makes it apparent she brings something to the table that’s otherwise being missed.
He asks: Why is she still hanging with her ex?
Cause there is still something there she doesn’t want to let go of. That “like a brother/ bff” is there and knows every single thing. Guess who she runs to when you mess up? He is basically a backup boyfriend.
You Forgot Your Common Sense 
If I have to drop my ex, you bEtter drop yips without me mentioning it. It’s that simple. If not you can get back with him.
I think thats fair