Ex's seem to get in the way too often....

So I started dating this guy a few weeks ago, he told me his ex still calls him all the time and he helps her out with stuff but then gets frustrated with her and says he's never going to talk to her again, he apparently did this right about our first date, I told him point blank if we started dating I would not appreciate him hanging out with her and helping her with stuff. He said he cut it off with her and told her not to call him anymore he b/c he was seeing me. He asked me on saturday if we could date exclusively and I said yes. Then he turns around and helps her with trying to buy a car on monday and tells me how pissed off he is at her for wasting his time and he told her (for the 2nd time in 2 weeks) not to call him again and to leave him alone...etc..mind you he was engaged to this girl over 4 years ago. I told him it seemed like he had some issues he needed to work out about her and maybe he needed some time, i didn't say we'd stop seeing each other I said he needed to make up his mind about her, then he just completely went psycho on me and started yelling at me not to push his buttons, if i felt that way it was my loss not his etc..and also sweared. i just told him i wouldn't talk to him while he was acting this way and hung up. i don't get it?? what should I have said or done differently??? he knew how i felt about this situation and then he proceeded to lie to me and go behind my back and see her????