Ex Fiancé Driving Me Up The Wall

He was with her for 4 years. They broke up. Haven't spoken in 2 years. Started speaking again about halfway through my year relationship with him. I'm trying not to come across as a jealous brat who wants to control his every move. So I haven't even asked what they talk about. Then tonight he says "I have a question." I asked what it was. He asked if she should come over and chill with him & his roommates. I said "ok." he said "are you sure?" I said "yea." But omfg. I am totally not ok with this for one reason and one reason only. She REFUSES to meet me. I have met all his friends. She is the ONE I have not met. I want to meet her. She has been dodging me and refusing to face me and quite frankly it's starting to piss me off. I meet all his friends. She will not meet me. It's ridiculous. He excuses it with "she has anxiety." Oh yeah?! Yet she can meet your new roommates and be totally cool with them??? Besides, I have anxiety too. I want to freaking meet her. So now he's with his roommates, his friend Chris, and her. They're all smoking pot. And where am I? At home. This. Is. Bull. I've said this to him, but he just keeps saying that he can't control who she wants to meet.