OMG, is this guy crazy or what?!

My friend had to deal with something similar. The guy was an aquarius, though. About the same age as your guy. He talked about how much he cared for her, etc. Then he went on a vacation with his ex wife and kids, because the kids wanted him to be there. Even though he claimed he hated his ex wife, his car was still at her house late the next night after vacation. Never texted or said anything to my friend for a few months after that. Then texts her saying 'Sorry my phone was dead' even though he had been contacting other people who my friend knew. Last I heard my friend asked to meet up with him so that he could explain things, but I'm not sure that ever went though.
This behavior, like most mentioned, isn't sign specific. But it certainly means that the guy is flaky and bad news.

All you need to do really is tell him you don't want anything to do with him and then ignore him after that.

What does 'dating but not together' mean? That you guys weren't officially a couple? Then you can't really get mad when he gets buddy buddy with other girls.

You can hate someone you were in love with. And what a winner.