Getting over him...???

So i was going out with this guy, super sweet, amazing guy.

Then, he kind of seemed less sweet, like he wouldn't say the things he did before and just all over different.

He would flirt with other girls, so i broke up with him.

Now that we're broken up, I can't stop thinking about him! He said he's over me to me, but my friend (who is a friend of his) says that he probably still has feelings for me, and that he liked me more than he had ever before. Is there any chance we could get back together? And how would I talk to him about it?