And I have this little insecure part of me that thinks he still loves his ex-girlfriend.

Like he says he doesn't, and I want to believe him.
But then he'll bring up mine and make a joke about my ex boyfriend, and if I return the joke he'll go along with it and everything,

But he sometimes gets really mad if I do this, after he does basically the same thing. And then he emphasizes how much he hates his ex and everything, but I personally believe that in order to hate someone, especially at that magnitude, you definitely still care for/love/or like them.

This could also probably be because he was with her for like, five years, and I feel like I have to compete with his history, which I know is stupid, but I can't help feeling that way?

I don't know, I'm really confused. :\

But I'm also kind of uncomfortable talking to him about this because I don't want to seem like I don't trust him, you know what I mean?