Why is my ex boyfriend calling and giving me insults??

ing me insults? He's been texting me and I've been nothing but nice to him ,yet he keeps insulting me and I just blow it off. This afternoon he called me again and when I answered he hung up. Then texed me saying I sound ugly as s*it. So I said "ok" and he saiid "bye" I said "bye" THEN hours later, he called again (I guess after he's been drinking with his friends) and started insulting me again calling me ugly and host of other things, so I just hung up. He hasn't called yet but I'm worried I ill have to kkep dealing with this crap. Why is he doing this????? 29 minutes ago - 4 days left to answer Additional Details He texts me things like "hahaha your so weird" etc, what should I do??,