Ok, that's good - you've admitted you can trust her, even tho that's at odds to what you wrote originally. I also think that it's at odds because if you did trust her then you'd not react so hugely to other guys - it's important to be honest with yourself. I hope this is true about trusting her tho because it's huge.

Have you ever tried writing down how you feel/thoughts going on in your head when jealousy takes over? Doesn't matter how silly you think it sounds, but be honest. Then, when you're calmer, have a look and see if things are actually as bad as your reaction showed. Try to give it a logical explanation, ie proof that someone talking to your g/f is going to take her away from you, or recognise that it is jealousy without foundation. I wonder if this will help because you said talking to your g/f calms you down. I wonder if you will start to recognise that jealous thoughts are not the same as reality as that will start to take away their power.

The other really important thing for me is for you to start working on your self-esteem. It obviously took a real battering with your ex, as that would've hurt like hell... I think that if you work on that too then you'll start to trust your g/f's words when she says that she loves you and will not cheat on you. And I know that you say you trust her, but although it's understandable that you're wary, a good relationship is based on trust and without it, life will be difficult.

Hugs