You could just delete him now with a message that says, "I'll contact you when I'm ready/you've matured/etc." Then just give it all time to cool off, give him the chance to realize you aren't going to put up with him while he's being like this and take some time away from him.
Honestly, I have never stayed friends with exes except one and we don't talk much. I have found that having exes around can kind of drag you down and sometimes they remind you why you stopped wanting to be with them in the first place. Not to mention a lot of guys are a bit weirded out when they meet a girl and find out she's still "good friends" with a guy she used to date (*ahem*andthensome*cough*).
This is just my 2 cents so feel free to ignore me. ^_^