It takes a long time to fix an esteem and jealousy issue. Trust- I know. I have the same problem but for different reasons. I love my boyfriend and know in my heart he would never cheat on me, but I'm always suspicous- always jealous. It's hard. But I try each day and I guess the only thing that will fix it is time and "corrective thinking."
Also, it helps when my boyfriend lets me know that he thinks I am beautiful or hot or whatever. His confidence in me and my looks, give me confidence. His words help me and give me more self-esteem.
I dunno what the purpose of this post is... I just thought it might be nice to know that you're not alone.
Hang in there. Honestly, I don't think it will ever fully go away, but I'm pretty sure it gets better.
Best of luck.