Need some reassurance about ex returning, help?! Kinda long!?

I think you can do better than a guy who with no real explanation disappears. I'm going to have to agree with his ex and say that he hasn't changed. He sounds selfish and clearly wasn't thinking about your feelings. He even changed his phone number, he may have had another girl on the side, unless you think he changed his number because he didn't want to even take a chance of talking to you. Whatever his reasons they surely can't be enough. You also probably won't believe whatever he says even though you are going to want to and if you are anything like me you will end up taking him back anyways, then the cycle will just begin anew. The only difference is that this time he will respect you even less than before and think that he can get away with more and it won't be long before he's trying. I really don't see a happy ending for you with this guy. Then again I don't really know him so take what I've said with a grain of salt.