What should I do about my ex not wanting to be friends anymore?

[rdeitjeri]

My ex-boyfriend called me on the phone a week ago and broke up with me. I was heartbroken. Then 2 days later he texted me and said he still wanted to be friends. Then 2 days later I hung out with his best friend who I've become friends with through my ex. He told me that he had a crush on me while I was dating my ex, and I kind of did too. We've talked about possibly being in a relationship. My friend and I had sex the other day. My friend accidentally let my ex find out. Then my friend told me that my ex called me a whore and didn't want to be friends anymore. My ex deleted me from Facebook. I still wanted to be friends with him. He shouldn't care what I do with other guys because I'm not in a relationship with him anymore and its none of his business. I don't want to lose him as a friend.