Ok...you are enabling him to continue this behavior. He says he can't call you while he's at work, yet calls his friends on a cell phone you pay for?! Now really, I'm not trying to bust your chops here....but you do see how you are allowing him to continue this behavior right?
If you're footing the bills....stop paying for the ones that he's abusing....i.e. the cell phone.
This is just an honest question....do you see the ways you are enabling his behavior? Of course he's not going to change what he's doing or how he's treating you....YOU are allowing him to treat you this way, and by doing so...you're inviting more of the same behavior. It's a mistake many, many of us (including me) make or have made.
Hon, put on that stylish stilletto you have in your closet and put it down firmly! He needs ground rules and you need to enforce them. Now I'm not saying be a bitch, but do stop allowing him to use you...and unfortunately that's exactly what he's doing.
Sounds harsh, I know....but you do need to set clear/firm boundaries.